polymorph:
Numbers don't say it all.
And yet numbers can often be important.
What a confusing dichotomy. I am glad we got this out of the way and can return to the subject now.
I'm an EAGLE user. I like it a lot. I'm prepared to buy a full-priced copy of it, should I ever actually do a commercial design (and one of the nice things is that I could afford to do so, even for a relatively small commercial design.)
But, If you're looking for a free program, download several, find appropriate tutorials, and try them out.
The "best for a beginner" one is probably the one whose tutorial you can manage to get working the best.
I've seen lots of people claim that Eagle is non-intuitive and has a "very old" GUI style (action/object based rather than object/action.) It didn't bother me at all (but then. I'm rather old myself.)
EVERY cad program I've ever heard of has had someone say "it has a steep learning curve." That may simply be because PCB/circuit design is HARD; there's a lot more to it than just a drawing program (or at least, there SHOULD be.)
(Well, perhaps not fritzing. Fritzing has a shallow learning curve, but a steep capability CLIFF. You can start off really easy, and then you get to a point where you say "ok, now how do I do X", and you discover that you just CAN'T, because there is no X in fritzing.)
Clearly the best free software for a beginner is Kicad.
The OP didn't mention what kind of computer they are using. I downloaded several copies of KiCAD for my mac, over a period of a couple years, and never could get it to work right at the most basic levels, so I gave up 
(maybe it's time to try again?)
I started using DipTrace.. Very nice program and is easy to figure out.. I still use it occasionally, but now I am making myself use and learn Eagle.. Seeing pretty much everyone is using it or has files available for it, makes it a no brainier.. As others have said when using the free version your locked into a pcb size.. That is fine, its amazing what you can do in such a small size.. For larger projects I still use DipTrace seeing they don't have a maximum size, but maximum pin count.. Download a few and find out what you like the most, but you might want to learn the basics of Eagle just in case..
May i join the discussion because i have nearly the same requirement. I would like to make some prototype boards, they can be small, not bigger than about 6x10cm. Today i installed Fritzing (on Linux) and while the User Interface is very compelling, it has the charm, as i understood, to order directly from this Application.
But then i wanted to add a part which was not in the database, an arduino328, and i was for me impossible to manage to create a new part, even with the docu.
I want to do small prototype boards from scratch and i would like to spend not much time on it (i would pay for an easy to use UI), as in understood, KiCad, but i would be also in the "mainstream" because man knowledge is around for product which are widely spread. Should i go for Eagle? Is it really so complicated?Is there a PCB designer where i can create own parts?
regards
With Eagle, you can download the design of the Uno or Duemilanove, and use that as the starting point for your design. Remove what you don't need, add what your design calls for. No need to start from scratch.
you can in both - KiCad as well as Eagle - create your own parts or you simply import libraries with that parts from others ... But especially in KiCad it can make sense to create your own library from scratch and add all parts you want to have available.
The effort to get familiar with the tool is for both more or less the same. I started originally also with Eagle but moved now to KiCad. As I already wrote: the approach is a little bit different between both. But that's only a problem if you move from one to the other like I did. If you start learning both are OK.
The greatest advantage of KiCad: it's real open software. Especially we as open hardware users should be aware of that point 
The tool will become better and better the more users work with it and give feetback.
Yes, open source is a very valuable aim, but i learned that "open source" is no end in itself. In the past, there were some occasions where it was no help in all circumstances and sometimes, when time is a factor, professional software has as well advantages, especially when the "closed source" software has a broad base of users. As CrossRoads mentioned, it is a help when this software is used widely, the community is big and there will be help around the corner (and some colleagues here are using eagle already for many years).
I am still not really sure, but i think, eagle is an serious alternative.
regards
p.s.:
hmm, no software is perfect. I downloaded a eagle version (eagle-lin-6.6.0) for linux, but i have already problems because the eagle version depends on 32-bit-compatibility libraries and it cumbersome searching the libraries, if it is possible at all.
yeah sure ... I also was unsure for a longer period if I really should move from Eagle to KiCad. And of course there are also good reasons to choose Eagle. At the end of the day everybody has to decide for himself which tool he wants to use - depending on the personal preferences.
One point against Eagle: I think the licence model of the new version is really a pain. CADSOFT now requests the ID of the computer you want to install Eagle in the new 7.0.0 version ... and you can install it only on two machines (PC + Laptop for example). This can cause problems if you move to a new PC for example.
Eagle 7.1 just out too. I'm still using 6.5.
mgcss:
yeah sure ... I also was unsure for a longer period if I really should move from Eagle to KiCad. And of course there are also good reasons to choose Eagle. At the end of the day everybody has to decide for himself which tool he wants to use - depending on the personal preferences.One point against Eagle: I think the licence model of the new version is really a pain. CADSOFT now requests the ID of the computer you want to install Eagle in the new 7.0.0 version ... and you can install it only on two machines (PC + Laptop for example). This can cause problems if you move to a new PC for example.
7.1.0 has changed the licence thing, but tbh, if you're a free user, you only have to register an email address. if you have 2 computers, just register twice?
I have full up version, but only 1 computer to run it on anyway.
Stupid me, i´ve downloaded eagle 6.6.0 and adapted it on a Suse 13.1, which was cumbersome because i had to find all the 32bit Libraries for the 64Bit Suse, only to discover that Cadsoft would offer a 64bit Version, egale-7.1.0. Ok, i should get used to the UI, but i haven´t yet figured out how to create a new part in the library, maybe this may be as complicated as in Fritzing, but maybe i need some more investigations. So, i think all products of this category have their pros and cons...
regards
Now i am at home and have downloaded eagle 7.1.0 for Mac OSX. While it was easy to install, i just can´t figure out how to create/modify a part, i tried it for Firtzing with the atmega328 and it was not working and with eagle i have not managed to import an library, which should be not ver complicated. So i overthink to buy an eagle version if i find an open source software, where i could manage to modify the parts i need.
regards
I'll do up a little tutorial on making a part when I get home. It's not that difficult, and gets easier with practice. Can really be explained in about 4 slides with screen shots, some arrows, and a sentence or two. I struggled with when I started too, until I realized it was just easier/quicker to start from scratch for each part.
Modifying a part that is in some other larger library, I find that hard too.
What is easy is to find the library for a part at Newark.com for a single part.
Or, open an existing board and use File:Export:Library (I think that's the path) and export all the parts on an existing board (Arduino, Sparkfun).
Ah, thank you, Crossroads.
There are some tutorials in the net, but when i try to follow them, it is like they have always a little different environment. I have already found the atmega328, but somehow, i am not able to get it in a project, when i create one. Maybe i have to learn a lot more, before i can start to assemble a board. I will make only very small projects, it would be sufficient to have a very simple designer, but it should provide a way to build or change parts by oneself.
regards
I think its what you are all used to.
I have not seen a reference to pcb spark which is free and has a similar feel to easy pc which i used to use.
I used to use orcad which was an expensive professional package , employer supplied.
Some pcb producers offer their own packages these days.
Design spark has no limitations and has an autrouter which i cannot comment in as i do not use them.
Downside for arduino is that there seem to be no arduino reference designs i can see although there is an eagle import library.
Also dxf output which i use for cutting solder paste masks does not seem to be read by some software.
Eagle has a limited free package that you can try.
If you have not used one before all i can suggest is you try the free offerings until you get a feel for the way they work.
Further to that, reread said eagle was dos era.
Easy pc was too i found the transition to design spark quite easy as it has a similar feel.
Nothing against eagle which many favour and have used once or twice but design spark is free and not crippled.
I think its what you are all used to.
A lot of people seem to expect a PCB design package to be like a drawing program, but it really NEEDS to do a lot more than that, and consequently is usually significantly different... (One difference is that you really want all the bits and pieces to have NAMES. Pin names, signal names, etc...)