Ok, my list of favourites:
#1: A1200. Compact and yet easily expandable.
#2: A2000. Built like a tank. EXPANDABILITY!!!
#3: A3000D. Standard SCSI & FF. And a lovely case...
#4: A4000T. Repairs flaws of the A4000D. Easy to upgrade.
#5: A3000T. Easier to upgrade compared to the 'D'-model.
#6: A500(+). The right computer at the right time. Upgrades are plentifull, but take a hideous amount of deskspace.
#7: A4000D. Castrated design. But hey, it's fast and it has AGA.
#8: A1000. Hard to upgrade, but it's where it all started...
#9: A600. Compact but hard to upgrade.
At the moment, I have both the A1200 and the A2000. The A1200 is heavily expanded, but still in its original housing (with a four drive SCSI-tower, though). The A2000 has some uogrades to make life a little easier, nothing more.
I didn't mention the CDTV or the CD32, as I don't think of them as being 'complete' Amiga computers and therefor don't fit in with the list above.
As a sidenote, I'ld like to add that I like all the models I mentioned above, but this is my list of personal favorites. I would love to have all of them, but hey, lack of space...