with technology improving, there is not big difference with USB or PCIe... same with Powerline, since max speed is whatever your ISP gives you...
USB for faster deployment, just plug and play..
PCIe you need to open the case and move shit around if you dont have room while still making sure airflow is not disrupted.
Powerline is good, just plug it into the power outlet.. but its more costly..
Valet by Cisco AM10 Valet Connector Wireless N USB Adapter
My vote, $20 cant go wrong.. bought 1 for my nephews desktop... works and pretty good..