Hi Bater These links might help....As you already had a custom made PC you will know what to look for. I know a guy who builds these he even has a stripped down version of XP pro that he installs to cut out even more none essential O/S crap. The type of sound card you need will depend very much on your budget and exact applications. No point in buying 32 I/Os if you only use 2.

http://www.endpcnoise.com/cgi-bin/e/std/sku=music_production_pc

http://www.echoaudio.com/Products/PCI/

http://www.soundonsound.com/sos/oct05/articles/emu1616m.htm


http://www.soundclick.com/bands/songInfo.cfm?bandID=687727&songID=5238055