Aside from bettering one's times in the various side racing missions, is there anything else to do in Vice City after you are 100% complete?

Nope

No more missions but GTA has great replay value. Whats better than randomly running around on a killing spree?

Ya there aren't any other missions when 100% done but its so much fun just running around playin taxi and just causin descruction all over the place with the tank!!! Lots of Fun. And does anyone know when the xbox version of San Adreas is being realeased??

If you've beaten any GTA game 100%, there's really no fun in it anymore.

Back yourself into a corner (underneath a rooftop), make sure you're facing a main road, and get out the Minigun. Nobody lives! Ha ha ha!!! And the heli's can't get you.

No, thats the point lol i love to piss around and waste time killing innocents and pissing off the cops SATISFACTION!