My 2 cents
HTPC is a very broad term these days. Basically because you impliment a system to output whatever it is you want, to your TV in so many different ways.
I learned so much in trial and error over the past ~10 years outputing things from my PC to my TV and I still feel there is a lot more to learn.
I think one thing to consider is if you want to tweak or if you just want a box that works. Right now I've settled on MCE 2005 (self built box) because I mainly wanted tivo like features. I picked MCE over MythTV mainly because I liked the added bonus of a Windows (XP) desktop in my HT for other things, and general ease of configuring (MythTV is easy but Linux+Hardware is not always).
Now I'm doing all this with standard tv. I don't have a HDTV yet (although I cry myself to sleep at nite wishing I did
). I think picture quality is fair but I still use a regular DVD player for DVD movies. Of course I can play other media thru MCE like DivX (mpeg4 and such) which is VERY nice when I need to get my hands on a tv show I missed or didn't know about or comes from a friend, etc. Plus of course archiving tv and other things now is extremely nice ability to have (althought time consuming).
And then there is the music. I am a big mp3 nut, having all my music at my fingertips is extremely nice. And with multichannel mp3 on the way, as well as all the other music file formats out there today, I'm pretty excited. It's almost relaxing to have all this ability sitting in one box in your HT, at least to me it is.
