In my experience, Pianoteq is by far the best in terms of raw playability. Nothing else I've found gives me a connection with the instrument that is remotely close to Pianoteq. Second favorite is the Garritan CFX. That's a large set of samples but is gorgeously sampled. Put on good headphones on and pick Player perspective. The CFX sounds HUGE, and with the exception of the missing vibration in the fingers, feels real. The CFX is a Yamaha and is thus a bit more strident than the Pianoteq Stewinway D4 simulation. Every time I buy another piano VST i get disappointed.

I am glad I don't need to spend more cash on piano vst since I have pianoteq.

I use addictive keys rather than Komplete/Kontakt pianos nowadays. They are bloody marvellous. There is a demo.

I have the full TruePianos.  It's light on the cpu and good for for practice and sketching out ideas.  But development looks dead, as its direct competitor, Pianoteq, left it in the dust long ago.
 
Nowadays, I use Addictive Keys Grand for everyday use, and either VI Labs Steinway or AcousticSamples Kawai Ex Pro for solo work.  
 
Still, for $80 (current sale price) True Pianos is a good value alternative to Pianoteq, since you get four piano modules and some control over the playing/sound, where as with Pianoteq Stage (the lowest level), you're stuck with what you have.  And the upgrade to the next level, Standard, ain't cheap.
 
Best to demo these pianos before you buy.  Your computer system plays a big role in the playability of these pianos, so you definitely need to try them out first.
 

I've been consciously ignoring Addictive Keys since it came out. I am well-covered for both electric and acoustic pianos and acquiring more would just be giving in to GAS. But...
 
Conopus' post made me go listen to XLN's Studio Grand, and I gotta say it's pretty darn good! Maybe even better than anything I've got now, including two other Steinway Model D's. Not gonna spring for 90 bucks on it, but there's a good chance I will grab it next time it goes on sale.
 

No one mentioned Ivory II here. I have it and it's right up there as my go to.

+1 for Addictive Keys forgot how I acquired it (m.friend/ swt water). One of them had a ridiculous looking deal a few years back, think I got it for 30 or 40 bucks (with 3 instruments). Turned out to be a great deal, couldn't get over how good this sounded (use 90% of the time Rhodes / 100% of the time if we are talking Piano), and I have tried many piano vst's. I can say with confidence that it was probably worth way more than I paid for it , and i would buy it again at a higher price if I needed to.(all a matter of taste and needs though).

Just to add to your options... Another nice piano in the <$100 price range is Acoustica Pianissimo.  Quite popular (It's been around  a long time), small footprint, and has a warm, round tone.  Still 32-bit only, however. 
 
http://www.acoustica.com/pianissimo/

If you want, I'll transfer my license for Truepianos $40... pm if interested..

I popped for Addictive Keys several years ago and have found NO reason to look any further for a better piano suite. It is an absolute must as far as the Grand and Upright, although, the Rhodes leaves a little to be desired. I use Lounge Lizard for my Rhodes and Wurlitzer needs.