Well, do like i do, get an 500, with al least 1mb ( i have 3 mb) of RAM, Kickstart 2.0 (to run Amiga 600 games) and an external floppy drive(s). Then, if you like it, get into Amiga, and search for Amiga 1200 with at least 030 (040 would be nice too) and Kickstart 3.9 (latest that you can run without buying a PPC processor). If you get into an Amiga 1200, you surely want to buy PPC processor and run AmigaOS 4.1, or at least 4.0. Then, get an Amiga 4000, with PPC and run AOS 4.1, upgrade RAM, and it will be great machine. You're all set! You should also get an 600, it's the tinest amiga. And when you will buy 1200 or 4000, make sure they're from Commodore, NOT Escom.
500- Amiga 500 and 600 games
600- optional, for that a600 games experience xD
1200- for games needing 030
4000- scene
But, the trick is, that you need to get PAL Amigas.
Also, if you're interested in modern Amigas you should get Amiga 1 G4 or an PPC Mac, that can run MorphOS. Eventually, download AROS to your PC.