Hiya.
What should I buy to get started?
Id need an Arduino, but what one? I want to assign values to different buttons, have them add together and be shown on a screen.
Lights to flash and things like that.
Aiming to eventually remove all the electronics from a table top pinball game and make it my own.
Sounds simple. But I want to make it more complex over time.
Cheers
Hi,
Have a look at the Uno on the hardware page (http://arduino.cc/en/Main/Hardware). It's the standard from which the others are derived, has a good range of shields to help the beginner get started quickly, and from what you've said should well cover your immediate requirments for IO pins and memory. Once you get started you'll have more of an idea what your next one will be too 
Cheers ! Geoff
If i buy these, would that be a good place to start playing?
http://www.skpang.co.uk/catalog/arduino-uno-starter-kit-d-p-554.html
http://www.skpang.co.uk/catalog/2x16-lcd-for-arduino-with-led-backlight-p-388.html
Here is what I think beginners should have as a bare minimum:
You would be better off with this too:
http://www.skpang.co.uk/catalog/digital-multimeter-p-770.html
Ive just ordered an Uno, some leds, wire, breadboard and some buttons. Is there anything else i need to get started?
Ive got a multimeter already.
If your only starting you will need some components to run the samples included...
It very much depends on what example you want to play with... here's some essentials...
Level 1: (the very basics)
Leds, Resistors, Caps, some type of sounder (piezo sounder it probably best)...
Level 2: (starting to experiment)
LCD and possibly a 4x3 or 4x4 keypad...
Level 3: (now your cooking)
By then you will have picked a project and will know if you need any extra parts...
Values of components can vary but be sure to have some resistors to limit led current, these normally range from 220 to 470 ohms...
A few caps are always useful, 10nF, 100nF and a couple of electrolytic 1uF, 4.7uF and 10uf... to start...
And possible a couple of transistors/fets...
Have a look at the examples and pick what you need from them...
Run some sample code and see how they work. Find a few basic arduino projects online and do them as practice.
Depending on what kind of display you want you may want to get some shift registers for multiple inputs/outputs ,
and/or actual display driver chips such as the max7219 for I think up to 8 regular 7segment led displays with dotpoint,
you'll need some transitors or preferebly mosfets(run cooler) to control any motor/servo/solenoids(andlook up flyback diode)
For lights you may want to look into higher power leds like common 1w leds, that bring constant current sources into play
that sounds like a very cool project
make sure you be very careful with your voltages,as I imagine this thing will get plugged in, line voltage is dangerous and anything that is plugged in has the potential to shock you, and always check that your power source is wired correctlyespecially if your machine has a metal ground, just today actually I plugged in a hammer drill to drive in a ground rod for a houses electrical service and whoever wired the outlet did so backwards, so imagine my surprise as I grab the ground rod and get electrocuted from one arm to the other, its not fun stuff and you don't want to be playing pinball and get shocked