Well I think having the 2.9's are a great start. I would add a NHT AC-2 for the center and a pair of 1.5's for surrounds. Any quality sub will help for HT. Outlaws LFM-1 will surely do if it's quality per dollar ratio follows suit with the rest of their products. You could also skip the sub for now and bi-amplify the 2.9's with NHT's SA-3 amp or use the Hafler for this purpose. There are lots of places on the net selling the vintage NHT speakers as used or NOS.
As you can tell I'm a fan of NHT and since you have a pair of one of their best speakers I would build the system around them if you like the sound.