I was actually wanting to ask the same thing. I've always had problems with Creative cards in the past, albeit they do have good sound quality (any X-Fi card). I've also heard good things about Auzentech, even though their reviews aren't the tops on Newegg. On the other hand, 3 cards from HT Omega are the top 3 rated sound cards on newegg, all of them the only 5 egg rated cards with more than 10 reviews.
My HTPC setup bit me hard in this arena. I was using the onboard soundcard, and I couldn't figure out why when I ran a sound test I could only hear the front speakers, and when I watched some of my videos, I could hear all 5.1 speakers. After much research, I decided to get a Logitech sound system from newegg that uses the actual 5.1 output on the card (you know, the 3.5mm plugs) and stopped using a $500 DVD player/home theatre setup I bought only 3 months before. Really sucked.
The problem for me was that my card could only output certain digital signals. Lo and behold I was unable to find a method that would convert ALL 5.1 and 2.1 output(digital or non-digital) to output via optical to my sound system.
I knew I wasn't always going to have a digital signal that would match 5.1 output for my home theatre system(like playing an emulated game, WOW,etc). So I had to either find a hardware/software combination that could correct this problem or get a sound system that could take the standard 3.5mm jacks from the output of my computer. After much searching, I decided to get a new sound system because the hardware reviews I read on hardware that could handle this said that the drivers/hardware were unreliable and crashed often. HTPC must be able to be up 99% of the time. Having shaky hardware for me was not an option.