Receivers

Whichever receiver you get, make sure it has HDMI inputs that can pass a 1080p signal, version 1.3. I think your first 2 choices do not. I like the idea of the pioneer elite sc07.

I believe you are expecting too much from the THX certification and name, which is supposed to make you believe that the electronics are somehow better for having the logo on the faceplate. Alot of it is media hype. It doesn't neccessarily mean that the amp sections in a A/V Receiver are more robust than anothers, or that ones speakers are better than those without the logo on them. As a sound field, it has been surpassed by Dolby digital and DTS. And they have been surpassed by Dolby digital-HD AND DTS- Master audio from Blu-ray. When you are watching a movie on a disc, you will find that most discs don't even have a THX audio track offered, as the newer ones outclass it.
I have a pioneer elite receiver with THX certification, though I never use that surround field. But if you do want to have it, check out the Pioneer Elite SC07 which is THX ULTRA certified and check out the price you can get if for on Videogon. I think you will be happy.