Your Preference U24, Xitel, M-Audio or Edirol ???

I have been reading up on all of the threads on using one of these devices from my PC (Dell PC - Windows XP) into my DAC. It looks like I need to buy one of these devices as the first step. I need some help on selecting one so any help you can provide or a preference would be much appreciated on one of the following:

Waveterminal U24
Xitel HiFi Pro Link
Edirol UA-5
M-Audio Revolution 5.1

Thanks and Happy Listening.