Name the top 2.
Alright, so I'm not talking about car models here, but manufacturers. I noticed I've leaned a lot towards the Grotti side (hadn't given it much thought myself, until it struck me that I own the Carbonnizzare, the Cheetah and the Stinger and they're my favorite Sports/Super/Sports classic cars). Hah.
Also, I really liked the Turismo from GTA IV which, as it turns out, is also Grotti.
My second favorite would probably be Übermacht. The Sentinel and the Oracle are really cool sedan cars, but in some ways I liked them more in GTA IV.
I hope someone finds this as interesting as I do..