Synthogy's Ivory goes where no virtual piano has gone before, sampling three full-size grand pianos to form a detailed library more than 30 Gigabytes in size.

DSK makes a decent freebie. Prova Piano is not bad . Jazz Piano is pretty good as well

I feed the mid track both the DSK and Jazz Baby VST's and pan then slightly. Add a pinch of plate reverb and you have something pretty nice sounding

All that said, if you have the means, some of the commercially available piano VST are stunningly good.