Without a doubt it is abosolutely and definitely the skyline GTR 34 vspec 2 nur, that is it in terms of looks, handling and power and it's also very exclusive. You hardly see r34 gtrs on the road as it is let alone a nur or z-tune (which is the best gtr 34 ever made). It has a legacy behind and it's also one of the most iconic cars of all time.
The gtr is a circuit car with a straight 6 twin turbo where as the other 2 are rally cars with 4 cyclinders and single turbo, so they're a bit different. So for me it'd be clearly the Z-Tune/Nur > 9 FQ360 MR/6 TME > RB22/P1 and incidently also goes that way down in price roughly.
I think some people are getting carried away with the sound the exhaust makes. A V8 muscle engine, now that's a sweet noise.