I have an Inspiron 1501 that's got bad DPC latency when the wifi is on.
I've tried an Atheros AR5BXB6, a Dell 1395, a Dell 1490, and an Intel 3945. All of them give me trouble, except that the Intel card won't even let the machine boot due to a BIOS white list.
Can anyone post a link to some reviews of various wifi cards? Ideally, I'd like to get one that has Bluetooth on it as well, but I want to know that it's got good drivers, works well with XP and windows 7, etc before waste any more money on another wifi card that won't work.