Don't take this the wrong way, but if the Linksys adapter works, duh! Get one like it.
I prefer PCI, but if the USB works, go for it.
I tried installing two different trendnet wireless pci cards, and it works for few minutes and then freezes up my whole computer. I sometime use my roommate's linksys wireless usb adapter and it works like a wonder. I run XP so there should be no problem with compatibility.
I need serious help with choosing a card which should work properly and ensure constant stable connection. I dont care if its pci or usb ... which ever is works better would be preference. I am looking for something not too overtly expensive ... something under $50 should be good.
I know that is it good to have the same brand wireless adapter and router, but I have yet to witness this. I was getting speeds much higher than my roommates on average(when it worked ofcourse). The router is a linksys by the way.