I'm running the kX drivers for Emu10kX hardware:
http://www.kxproject.com/
Works for Audigy 1s, SB Live! Series. You can route a 2 channel signal through it's DSP filters and tell it what to do: surrounder, copy channels, echo, delay, etc.
Doesn't work for any of the new 24 bit SB Lives or the external creative hardware though. If you want to use them, check compatibility before you buy.