I'm building a new HTPC to replace the ancient Mac mini. Definitely going Windows, and I want it to be powerful enough to play Steam games for a while to come.Crab People Build
I expect to get a slower processor (though that one is the plateau of the price chart for Core i5s), better motherboard, etc... Mostly I was just scoping out the rough price. As much as I would like a Mac mini, the price-to-power ratio is ludicrous.
On a side note, RAM is so cheap it's practically free. I think I'm doubling the RAM in my primary PC (the old Core i7 920) to 12GB. I actually use it with the video editing. =P