I'm a computer person, built many, watched TV on my Mac IIx without issue about 20 years ago, but I can't say I am real pleased with my HTPC experience over the last 5 years. I have cable TV and internet (TimeWarner) with a DVR included. Approaching the ease of use of that DVR has yet to occur, and seems a constantly moving target, so I continue to pay each month for a DVR I assumed I would be rid of two years ago. The potential for playback of a wide variety of media files has been what has kept me going with the HTPC.
When HTPC works, its really very nice. I have hundreds of movies ripped, many thousands of music files, but its like owning an old sports car, constant tinkering, poor reliability, but again great when it works.
I would not recommend it to anybody normal, and doubt I would repeat it knowing what I know now if starting over. I would build a straight up PC for fun and games, a network storage device, and use something like one of the DLNA BluRay players to feed the TV and AVR.