For paid software i would consider ivory piano or galaxy d for kontakt which the one i own. I can get bright sounds (yamaha) or jazzier (steinway) with galaxy d. Driving them with my roland stage piano as midi keyboard produces an almost perfect sound of a well recorded piano. (nothing replaces the real thing) I'm primarily a piano/organ guy.
For occasional piano sounds, or for a tool to understand harmony, theory and for productions where piano is not the crucial sound Try the freeware piano one vst.
A good pianist with a sustain pedal and a good midi keyboard (preferably one with hammer action) can make any of these sound good.
Tell us more about you and i might be able to help you further. 🙂