Good luck! I just went through two T743s... both went back. Both had hum (only with certain Dolby Digital 2.0 sources), and one had worse hiss than the other. Neither sounded as "lush" as my classic 7240PE. I'm seriously considering picking up a 3240PE to run rear channels and calling it a day.
Of course, SpearitSound accused me of "looking for problems" --> but these forums have provided a solid sanity check on both issues. To their credit, they tried to make me happy.
The NAD's don't have firewire, HDMI, or DVI. Depending on your budget, your room size, the speakers you choose, and what you want your receiver to do, there are many other options.