Best HTPC setup

There's tons of good info out there... it gets a bit overwhelming. The last time I built a computer was 1995, and I pretty much just threw components together without thinking much about it.

Now, if I build a computer I'm wondering if I get the cheaper Intel E4300 and overclock it - which seems the best value, but I wonder about cooling. I'm still trying to figure out what kind of video card i really need to play the h.264 content that I might use. Then there's the linux vs. microsoft -- i'd go with microsoft just b/c of the perception that it would be easier to setup like a set-top box except, I keep thinking i can probably save a few hundred dollars in hardware by using the less resource intensive linux... Setting up linux and mythtv isn't that difficult at all... i'm just not sure how well remotes will work, online services (buying movies), etc...

fun stuff....