I'd be interested to know how Alicia's Keys measures up to Truepianos. There's a free demo of Truepianos. Did you try it or pianoteq before you bought the NI soundpack?
Lucky you having a Steinway.
I have two CM-30s which I use for monitoring at home and as my smallest PA for gigging. They're great. Rather have a Steinway though.
The Steinway was from inheritance money, and it was pretty inexpensive for a Steinway. I just had to put $3000 (rebuild with my huge discount) into it immediately after purchase. It's a fully restored 1916 model M. The A string on that model is about 5" longer than on a new one. So it's like having a 6' grand in a 5' 7" box. Plus the wood of the soundboard is just fantastic. I had it rebuilt with a modified Renner action, and Abel hammers. I had slightly stiffer return springs put in so that the keys return faster. Action at middle C is 47 g instead of the standard 52 g. Very light. It did make it difficult playing on a former teacher's beast (57 g at middle C -- the person was sadistic toward students) which was funny since we had the same tech.
If I were to buy a newer piano today, I'd go with Yamaha because Steinway hasn't been very consistent over the past 30 years.
I didn't try Truepianos. I went by several posts over on DUC (Digi User's Conference) that were discussing various plugins. AK is really nice sounding. You can orient the piano stereo from looking at the keyboard as a player or from the listening point of the audience (which I use extensively). It has the mechanical noises of the pedals and action, too. You can also adjust mic noise and "tube" saturation if you want a more "vintage" sound. People have had problems with Kontakt 4.0.1 with this, but they tell you to update to Kontakt 4.1.1 and that eliminated the latency issue.
But with MIDI, even the 2.9 ms latency (Truepianos) will bug me in a mix because I will compensate for it, and this is why I needed a keyboard with its own sound and a dedicated amp rather than a straight MIDI. So I'll be listening to the Alesis sound while playing, and then have the AK sound recorded when I'm playing with others. Solo it won't bother me. My quad core doesn't come close to any problems even with Reason 4 and PT running.
Truepianos does not have an RTAS version for Windows. For Mac, yes, for Windows XP no. To use with PT, I would need to go through the fXpansion VST/RTAS wrapper -- and this introduces more latency when recording.