The PCI WLAN card is a lot better than the USB thing. Features, connectivity, power etc etc can all be rightly configured with it.
It's a lot more reliable since you're going to be working from a stationary place and aren't planning on moving around.
If you do encounter problems, it is very simple to just add a pigtail or change the direction of the antenna/s.
Hells!! Even a patch of copper cutout stuck to the side panel of the case will give you amazing reception.
The USB Wlan adapter is pretty unreliable when it comes to removing and putting it back in 10 times a day. Drivers, USB recognizing factors, loose contacts, port speeds , port current etc etc add too many complications to having it on a stationary rig. It's ok for guys who are mobile all the time, since they accept a level of wear and tear over a period of time.