I think pmc is on the right track. The sounds you use are ultimately up to your own ears, but as with a lot of electronic equipment, the design team's ethic/priorities DO kind of reveal themselves over time. Its the interesting blend that makes Korg & Roland presets really pop out at you, whereas many other synths are more hit-or-miss. Not to dis Kawai, for instance, but their synths, though useful, have rarely been all that populist anyway. That's just the esoterica of synth design for ya.
Also...piano patch quality is always a big topic, but the truth is that aside from the real thing or perhaps the GigaSampler, "real" piano is a silly grail. One can always find fault with the nature of the attacks or the short tails or what have you. Be aware of your environment. Nobody has ever asked me when I played live "don't you have a piano wave with a more solid midrange and better resonance characteristics than that?" Unless I was sitting under 2 fancy Neumann mics in a $1200-an-hour pro studio with a Bosendorfer Imperial Grand in front of me, what's the diff? I started on piano, I grok the debate, but don't pucker unduly over it.
Best compromise: double/split the piano waves you have for added oomph and tweak the effects thereof or land something fairly satisfying like the very crisp Oberheim MiniGrand module. Aside from polyphony isues for Rachmaninoff freaks who would choke a mere 32-voice machine to death, you'll get a musical sound. If you hit the studio, use their big ol' sampler if you like, but don't split hairs to your own detriment. I now HAVE a viable piano sound to use, plus the additional universe that came along with it; 6 years ago I had no instrument at all for a time. AHEM! Perspective, guys.