My XFI Titanium has given me 100% perfect and reliable audio with the exception of only 2 times ever, and I bought it a good while ago... Possibly 4 years too.
The first time it went funky, Ireseated it and that cured it but the second time was a little more problematic.
I uninstalled EVERYTHING to do with the card, and I do mean everything, I even when and looked in all teh PCs nooks and crannies to seek out any remaining Creative debris, and trust me, there was a fair bit, and once I was happy that I could get no more, I installed the card in a different slot.
Been flawless ever since.
I have now swapped it for a Xonar and sure, the xonar is possibly a tad better I grant you, however, I use the junk on the drive bay box, and while I have now also added a FrontX panel, I cannot at this time add my Guitar to it like I used to on the XFI, but at least I got Firewire back.