My favourite cars are:
4x4: the Patriot definitely! It looks so great when being 'swingsetted'! And the fact it can climb through traffic.
2 door: Sentinel (goes bloody quick, and the one with the body kit is very cool)
4 door: Primo ( it just looks like those HK taxis (Toyota crown comfort) & I usually use it to have fun.)
Sports: Turismo (for its handling and brakes), Infernus(for its looks and rarity)
Other: Fire truck ( it's fun hosing people down ), Securicar (it has a hell lot of $$$ when you blow it up)
bikes: NRG-900 (its looks, stunting abilities), PCJ-600 (same for NRG)
Boats: Jetmax (its sleek look)
Helis: Annilator (whatever it's spelt) ( this can kill in 1 shot! )