whoever told you that usb wireless adapters arent reliable is prolly using the 10 dollar one. I've got 4 40 dollar trendnet mini usb wireless adapters running my computers in my shop, and I can assure you they are 110% perfectly reliable. they even out distance the one computer with the wireless pci adapter, so dont think you get shorted on the range either.
TRENDnet | Products | Wireless N Speed Adapters | TEW-649UB is the perticular model that i'm using.