I have an M-Audio Delta 410 and I connect it directly to an amplifier. I guess some people just luck out where electronic noise is concerned because I haven't had a problem in that area. Honestly, though, if you already have a preamp or a receiver, it might do some good to compare the sound using each possible configuration. There are quite a few people at the avsforum who stand by the pre/pro capabilities of an HTPC, but the software isn't always there depending on what soundcard you buy. So, in summary:
* You can use the analog outs and decode multichannel audio from your HTPC using software or hardware (depending on the capabilities of your soundcard -- the Delta 1010 and the SB Audigy 2 Platinum Pro offer external hardware that make EMI concerns inside a computer moot).
The drawbacks here include possible electronic noise/interference (for those cards with no external hardware) and lackluster software.
* You can use the digital out and decode multichannel audio with a preamp or a receiver.
The drawbacks here include added cost and the fact that your home theater will take up more space.
- David
