Not knowing if you have a price point to work with, but speaking to AV-Reveivers I'd concure with Arups Yammi choices.
Would definitly agree with Arup on the Yamaha models mentioned excellent units. You might look into Nad, B&W, & Rotels top line AV units. There are others, but the price points increase heavly.....
Totally off subject: Now if the power would just stay on for more than 5-min. Severe weather has torn many of the US states up badly. (TWISTERS) It was our turn last night. No twisters here thank god, but severe storms tore us up pretty bad.
In the $630 price range you can find a Sony STR-DA4ES on your doorstep. IMHO It runs very, crisp, clean 110W/ch power for 7 channels. It's very tweakable and has a decent interface to work with. I'm very pleased with mine even though I find many people like to bash Sony. The 5 year warranty is also hard to beat.
I'd strongly second the Sony 4ES at that price. I used a Sony 333ES, same power and ajustability features but only 5.1 and lacking component switching and it was an excellent receiver.
If your budget can stretch to $850 (online from ETronics) consider the Pioneer VSX45TX. Very good processing, killer MCACC auto-calibration feature, plenty of power and very flexible and easy to use. Not recommended for 4 ohm speakers though.
It's good to see a fellow NHT owner. I recently purchased a Evolution setup as well consisting of T5 towers, M5 center, and some CS 8.3's for surrounds. I'm powering everything with a Pioneer Elite 45TX. As Steve mentioned the MCACC is the best thing since sliced bread, and the sound produced through the NHT's is phenomenal. It has no problems driving my T5's. Highly recommended. Let me know if you have any specific questions.