I have an M-Audio Transit USB sound card. This is good card; the sound is very decent and price is very good, too ($70). And M-Audio claims full support for Mac OS X. Also, there are some raving reviews around and so on, so I bought this card, installed the very latest drivers from M-Audio site and very soon found that after a long sleep (one hour is enough), this sun of a gun freezes my laptop (TiBook 1Ghz) to death if plugged in afterwards. Nothing works, just mouse moving and only a hard reset can revive my laptop from its coma. M-Audio support is full of brilliant comics -- they answered that this is the known issue and they'll fix it eventually. Then they gave me most useless advice I ever had from support people -- don't use sleep in your laptop. I wonder if they know what a laptop is.
I'm a sysadmin from the old school, and can't be scared away that easily. So after some digging into this problem I found that their buggy driver is the culprit. In short, it looks like it doesn't clean up after itself when unloaded, and when it's loaded by the kernel the next time, something is getting severely corrupted and plugging in a card again will freeze the whole system. Also this card doesn't have flash memory, so every time you plug it in, someone needs to load firmware into this beast to make it work. This "someone" is a daemon that comes with the driver package and resides in /Library -> StartupItems -> M-Audio Firmware Loader -> M-Audio Firmware Loader. If you run ps axw in a Terminal, you should see this process after driver installation.
As soon as the firmware is loaded, this card acts like totally normal USB card, complying with standard audio USB protocol. And Mac OS X (10.3.3 at least) has a generic driver for such devices! We have an alternative now -- just need to remove M-Audio's clumsy drivers from system, but keep the loader in place. When I did this, the card was recognized by system's own driver and has worked flawlessly since. The only thing which is missing after that is the latency tune up option; otherwise, Audio MIDI Setup.app from Utilities does everything that the M-Audio preference panel does. Here is procedure:
Mac OS X Hints
http://hints.macworld.com/article.php?story=20040514125451790