I JUST built an HTPC and it had very similar components, but was much less expensive! The parts listed below with the rebates is only $400 or $410. Its only around $450 if you dont do the rebates. And this is a very high powered system and very future proof in my opinion (Sata III and USB 3.0 and the lot)
Here was my build if you want to compare it. I also suggest a different processor than your choice. The 445 x3 Athlon works perfectly, is only $77, and uses much less energy. The only real difference is the L3 cache, which I dont really see you having to use anyway (I certainly dont), and even if you do use it, it probably wont be often enough to really make that worth the energy and the extra money (in my humble opinion anyway).
$30 with the rebate!
Honestly, my system idles at 70 watts and maybe goes to 100 watts. Even with bluray and other thigns, this should be fine. The whole hype of really high powered PSUs seems stupid to me when this is more than enough. Is also very energy efficient.
Couldnt really tell you the voltage because Im at home for xmas but I never changes the voltages, so whatever is standard. Its definitely not abnormal though, just look at the 445 in Toms charts, I think they got around 74 watts idle for their system in the tests.
Temps were normal whenever I checked. Usually between 40 and 45.
Whats 'Way too much' though? If you have any other questions just let me know!
Btw, I read as many reviews as possible before buying parts, so you can trust that those parts are pretty good (but of course reading the reviews yourself wouldnt hurt!)