If you only want to play games and do some tracker stuff, you could do very well with a standard A1200 with 4MB Fast RAM and a harddrive. If you don't mind a bit of yellowing you should be able to grab one on Ebay for under 50 Euro.
If you don't want the hassle of playing games from floppydisks, you should consider adding a 68030 turboboard and install WHDLoad. The best card you can get is the Blizzard 1230 Mk.IV, but they tend to be rather expensive. Look for an Apollo or GVP card with an 68030 at some 25 to 30 MHz, those will do the trick just as well and are a lot cheaper usually.
