As far as soundcard goes, if you're looking for a cheap, high quality PCI sound card, definitely check out the Chaintech AV-710 (www.newegg.com). Is about 25 bucks, 7.1 surround sound, and really good quality for the price. Definitely worth checking out if you're in the market for an internal sound card.
Kinda sucks that you bought the case. Since ITX has weak sound and graphics quality. A uATX or similar can give you a full functioning setup cheap and easy, but the PSU and cooling demands get steep.
The VIA mobo's have a tiny L2 Cache(sp?), 64k compared to 512k which is nice to have to multitask, but if you're running just mp3s and cds than its just fine.