I have always stuck with creative for a sound card, the X-Fi series (IMO) is good and reasonably priced.
Onboard is getting better but its no substitute for a dedicated card, though DX10+ renders the difference moot since it takes out the hardware acceleration for sound processing. OpenAL doesn't do that though and many games are using it as standard now over DX10.
The high end X-Fi's or any cards with memory on them aren't of much use to the average user, games don't take advantage of it, etc.
I installed that one for a friend and he hasn't had any complaints, just make sure you get the drivers from the website, the ones of the CD are usually old and crap (once I got driver CD that wasn't for that device).
EDIT: If you want a cheap alternative to the X-Fi look at the Audigy cards, they are about half the price.