^ To use the 5Ghz band, you'll need the WUSB600N, else you'll get regular N speeds on 2.4Ghz. It doesn't make a difference for G.
Edit : I'd always advise you to wire your main desktop to your router, nothing beats Gigabit speeds and reliability. You can use wireless for the other devices around.
Edit : I'd always advise you to wire your main desktop to your router, nothing beats Gigabit speeds and reliability. You can use wireless for the other devices around.