I currently have an Audigy 2 ZS Platinum. It permits me to insert a 1/4" jack line from bass guitar and play along with pre-recorded piano music. This worked fine under Windows XP.
I am moving to Windows 7 64 bit (dual boot for now), and Creative may not develop fully working drivers for this component. Looking around, I don't see Windows 7 support mentioned at product web sites from E-MU, Roland, M-Audio, etc. Even at Creative, the posting of available drivers for Windows 7 is deceptive, as they do not adequately support recording (latency, distortion). My local music store shrugs and says to stay with Win XP. In some cases, the Vista drivers will work in Win 7. So I need real world feedback on this.
I should also mention I'm not impressed with available USB interfaces - they have too low of a signal to noise ratio for my purposes. That leaves PCI, or possibly firewire devices (never tried one yet).