One thing about having a tin ear, I save a boatload of money. I like TruePianos. Sounds like a piano to me. 

TheMaartian
and yup, I prefer playing modeled velocity-sensitive instruments vs. sampled ones. 

We may be in a minority but I agree. Whether the sound is EXACTLY the same or not matters less to me than the potential for expressiveness. I haven't used a sampled Rhodes sound since Lounge Lizard came out.

I do not think you can beat Synthogy's Ivory series.  Their American Steinway is pretty affordable since it just comes with one piano (as opposed to the three piano Ivory II Grands which is what I have).  Free is nice, but if you use a lot of piano, you will not regret this purchase.

I don't mean to call seniority here, a lot of it is personal taste, but as a full time professional pianist I agree that Ivory is excellent and easily better than 99 percent of other stuff (of which I have a lot, including Addictive Keys and NI Komplete Ultimate). PianoTeq is worth checking out too though. It's different but can sound really alive.

Sanderxpander
I don't mean to call seniority here, a lot of it is personal taste, but as a full time professional pianist I agree that Ivory is excellent and easily better than 99 percent of other stuff (of which I have a lot, including Addictive Keys and NI Komplete Ultimate). PianoTeq is worth checking out too though. It's different but can sound really alive.

Ivory is most certainly excellent - but it's freakin' huge and hungry too:)

kevinwal
One thing about having a tin ear, I save a boatload of money. I like TruePianos. Sounds like a piano to me. 

Hah ha!!
 
Agree completely

will sell my full edition of Truepianos for £20!
Redundant since using EWQL pianos which is a monster of a library!

Pianos are my bread and butter, and I agree with those that are saying True Pianos is a good choice. They have a great modelled sound, and the hit on your CPU is so low you could host a piano quintet without breaking a sweat. However, I do think to get the best 'Grand Piano' sound from TP you will have to pay for the Atlantis module. (hint: it's worth it). Whenever I am starting to write or record a piece, I almost always use True Pianos, and often never bother switching to another instrument. This is a great sounding piece of software and I think Sonar is a much better piece of software from having this program in it.
 
If you are looking for an good all round Grand Piano sound for free, look no further than the pianos installed with Dimension Pro (or Rapture Session now). They are not necessarily the best out there, but if mixed with other instruments as part of a band, the sound is more than passable. (and they're free!)
 
I will add that if I want a true piano sound I will mic up the acoustic piano. There is no comparison as far as I'm concerned, I've yet to hear a model or sample that comes close when compared side by side to a real acoustic piano.
I will then add, that the wording here is important. You notice I wrote "when compared side by side". That's because sometimes it is almost impossible to tell just by listening to a piece on it's own, whether it's a real piano or a software one when played and mixed well.

Elffin
will sell my full edition of Truepianos for £20!
Redundant since using EWQL pianos which is a monster of a library!

I just sent you a PM