I'll also throw in a huge thanks - it works great on my Sound Blaster X-Fi Titanium (it's a newer PCI-Express card) with a P6T Deluxe and OS 10.5.7. Now I don't have to change between the lousy SoundMax and the addin card all the time when switching between OSX and Windows.
I don't have any SPDIF or surround equipment to test, but SPDIF shows up for both input and output, and stereo analog output is superb.
Mic doesn't work though, and the prefpane version causes occasional playback stuttering (but since I don't get anything but volume controls enabled in the prefpane anyways, it's not a huge loss). I'll speculate that the mic issue may be due to the way the Titanium has a configurable mic/line jack, and it's just stuck at line level.
The only other glitch I've found so far is that the volume is muted after resuming from sleep despite OS X reporting the volume at the normal non-muted level. Clicking the volume icon and rolling the mouse wheel does well as a workaround.