+1 for True Pianos. I have tried alot of them but will say my needs are ONLY to sit in ROCK mixes. If you were playing classical piano solos, not sure which piano would be best but the fact that TP sounds good (has a few different pianos) and the presets give you quite a bit of range to find a piano sound that fits.
The best part is (like Pianoteq), it isn't a pure sample playback module but in its case a hybrid but doesn't take a whole lot of RAM. I have three instances loaded in a track, sitting side by side with three instances of KONTAKT and all is fine.
I was using BLACK GRAND by Sampletekk (which I like) and the three TP engines use less resources than the light version (No 4) of Black Grand.
Now, it also isn't that expensive and as mentioned, free upgrade to version 2. Which I hope allows a bit more tweaking into the engine (EQ, pedal sustain volume and time, etc).
Jim