My 2 cents worth:
Advantages of A500: lots of older games will work.
Advantages of a1200: faster, easier and cheaper to get hard drive, which means that lots of games can be installed on a 4 gig hard drive, prettier graphics, many a500 games can work if you use WHDload,. Hard disk installability is something you will not go without once you have experienced it.
Go for A1200..
