My M-Audio MobilePre has done sterling work over the years. Barely perceptable latency has made recording in music software easy (or at least limited only by my skill) and as an external box it’s easy to access all the sockets.
Only I changed the sample rate, for no sane reason, and then discovered that I couldn’t turn it back again. That wouldn’t have been a problem apart from the fact it did something unpleasant to the sound output.
Every time I opened the control panel the latency and sample rate options were greyed out. Thankfully I found a solution from the M-Audio forums here, though if you keep reading I’ll explain for Windows 7 (should work on Vista as well).