This is a tough one, especially as i don't really know which i consider best, all were mad / fun / nice in their own ways but i suppose....
1998 M3 Evo was probably the best all rounder, it only had 36k miles and was absolutely immaculate, not one mark / ding or scratch!
2nd was probably the Evo VI GSR
Then it's a choice of any of the more modded / fun cars i had....
Pulsar GTI-R, 280bhp, 4-Pot Godspeed brakes, endless list....
Renault 5 was fun, constantly went wrong and cost a fortune but with over 200bhp it would embarrass just about everything i ever tried against (i was 19 at the time so i'm allowed to say i went around racing people)
Dimma Clio was quite cool, i always wanted one as a teenager so enjoyed owning it before the Pulsar