I'll try posting this in this thread in hopes of getting a bit more response as the HTPC forum didn't really get me anywhere.

Currently, I'm planning on purchasing the Sharp Aquos LC42D64U. I also currently have Klipsch Promedia 4.1 computer speakers. I'd post URL's but its my first post and the site won't let me.

Once buying the TV, I'd ideally like to use on of my spare computers as a multimedia player (DVD, xvid rips, random videos etc.) I guess my main question is, what kind of sound card and cabling will I need to successfully run my SD/HD audio through my soundcard/computer and have it play on my computer speakers. Is there any downside to doing this (ie: loss in audio quality). Also, will a standard onboard video card with VGA output be satisfactory for outputting the video (most DVD's or xvid rips) to my TV(it has 1 VGA input), or will I also need to purchase a better video card and use dvi->hdmi converter for a better output/resolution. If it helps, the spare computer I'd plan on using is an AMD Athlon 3000+ (2.2Ghz) with 1gb RAM complete with generic onboard parts(sound, video, nic, etc).

Thanks in advance for any help or advice.

Your VGA will likely work fine. I'm driving a LC52D92U using a Mac Mini, which is about as wimpy as HTPCs come. However, if you want to use the Microsoft media player for DVD playback, you have to use DVI/HDMI to the TV, else it will complain it can't establish a HDCP protected link (I had this happen on a regular display after "upgrading" from version 10 to 11).

To get surround sound from the TV, you will need an optical S/PDIF input on the computer, and some dolby digital decoder software. That might be quite hard to find. It might be cheaper to put the TV, and the computer, through a cheap receiver that can do the decode instead.