A Sam Coupe! :-D
Seriously, I have a C128 that was great, and used for serious stuff until I got an A2000 - that would probably now have the harddisk and all the goodies they can run these days had Amiga never hapenned ... though I did try to towerise an Amstrad 6128 once too.
Oh, and then there's the Atari ST, which would have seen much more action had the Amiga not been there to squash it ...