IMO the perfect Amiga is as follows:
A1200 in original desktop case
030 accelerator (preferably Blizzard) with fast RAM on board
Compact flash to IDE adapter with 4GB card
PCMCIA compact flash adapter like EasyADF
Lots of WHDLoad games 
This is having gone through two basic A1200s upgraded to the max into towers, plus an A4000D similarly upgraded, and all sold and gone back to the setup above
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moto
Replace the 030 accelerator with a PPC and a Graphics card (yes that is apparently possible in a desktop case) With OS4 on a separate partition and i'd agree with you. the Desktop case just can't be beat, but I do appreciate a crazy 1200T setup.
