For me the 458 Italia is a return to the glamour and extravagance of the 355 and 348, somehow this was missing entirely from the 360 and 430. The 430 I still ranked 4th because it does have considerable muscle in its design (especially from the back), but it lacks the glamour of the 458. The 360 pretty much looks like a toy.
I'm not sure how the 458 will look roofless, it doesn't seem like it will be as hot as the 430 Spider. But we shall see what the guys at Maranello can do.
EDIT: Just realized that my list is pretty much identical to Merc1's. Haha, we seem to have the same taste.