Suggestion for a starting board?

Hello eveyone, I'm completely new to Arduino and am looking into buying a first kit. I have a doubt about which board to get, since I know that I will play with it for a long time. Basically, my doubt is should I get the UNO board or simply splurge and go for the Mega2560 (or maybe something else)? Will the projects that were designed for UNO (usually those starting ones are) work with Mega2560 board? Since I never played with them, I don't really have a feeling how much more "powerful" is the Mega board (or better to say, how many more features it has, and how useful is that)? I would really appreciate if someone who had some experience with both board could coment. Thank you

Mega is no more powerful, it just has more resources to play with. Still an 8 bit processor running at 8 MHz with the same (or nearly same) instruction set. You can do a lot with Uno and 20 IO, and when you accidentally smoke the processor you can pop it out and put another in. If you needs some more IO, an extra shift register chip or some kind of driver will often suffice. When you get really complicated programs that need more SRAM, or more IO, or more PWM outputs, etc, then look at bigger chips, like the '1284P with 16K SRAM (twice that of the Mega) and 32 IO (12 more than Uno) including 2 hardware serial ports - maybe you won't even need an extra IO chip. And the '1284P is still a DIP in case you smoke it. Later a Mega when you need 4 hardware serial ports or have other needs. '1284P Kits available.

The main difference between the Uno and the Mega is that the Mega has a lot more I/O's.

Normally all sketches for the UNO should run on the Mega.

I myself use an old Mega for prototyping and when testing is finished I make the final design with whatever Arduino is suitable (mostly the Uno if it has enough I/O's for what I need)

Thanx for clarifying that. I guess then I'll start with Uno and see how far that gets me... :)