ATM I am using USB Creative Labs sound cards. These machines are used for simple "Highlight capture" for sporting events. No actual asio drivers just the standard WDM drivers that came with the sound device. (Creative Sound Blaster X-Fi Surround 5.1 Pro USB Sound Card | Creative Labs Online Store)
Eventually I will be upgrading these to http://www.bswusa.com/USB-Interfaces-Henry-Engineering-USB-Matchbox-II-P2601.aspx for direct interface into our mixing boards.