My opinion.... don't do a tower the 1200 looks great with that small form factor... if you need a more space for cards and such get a 4000....
Agreed. Obviously it depends on what you want, but a desktop A1200 with an '030, and *maybe* a scandoubler is the perfect setup for games, maybe a faster card if you're into demos.
For RTG related things, a big-box amiga or (IMO) WinUAE is the way to go.