IMO, the biggest benifit to HTPC's over other hardware is the various HTPC interfaces. I'm a total MCE fanboy. I love XP's MCE (Windows XP Media Center Edition 2005) interface and Vista's (Vista Home Premium or Ultimate) is even better. There are other good ones that just install on XP (and Vista I'd assume) like Sage, BeyondTV, etc.

Having a remote that drives 99.9% of my computer is just plain nice (because of the interface). If you have never seen MCE in action you may not know what you are missing, or other HTPC software(s). It's true most HTPC software IS geared for DVR functionality but I like MCE the best because of how it handles ALL of my multimedia. I would not want to go without my music library or videos, or pictures, or movies (MyMovies plugin for MCE). And of course having the DVD player built into the interface as well.

Basically my computer has blended into working just like any other stand alone DVD player or DVR/CableBox or CD Player, etc. I do have the keyboard for when I want to go above and beyond, like browsing the Internet or playing a game.

Toss in one other goodie for MCE, extenders. The Xbox 360 is a generation 2 Media Extender. You attach it via your home network to your main MCE machine and it gives you the same interface and ability to play all the same multimedia content you have on another TV elsewhere in your home. I have several friends that have a 360 just for that. I am planing on getting one this summer.

That is why I love HTPC's so much.