Mike, if it helps... the technology in the t chips is the same as the normal chips, they just have limits put on them to keep them within the thermal and power package. When I was planning my HTPC I did look at them but the advice I got was that they're suitable if you're a system builder and want to pick a TDP/power consumption, but for an end user they're not so great.
I'd go for a system with a PWM CPU fan set carefully so that it is silent except if there's a need for it, and I'd go for a normal CPU. That way the only time you'll hear it is when the CPU is under such sustained load that it gets to build up heat, and at that time I think I'd suffer a little noise for the extra computing power. The alternative is that your system runs hot under load but silent, and less powerful.
Ivy Bridge is Ivy Bridge, there's nothing different about them other than the limits imposed to keep them within the tighter spec.