Sure, you'll be able to use any USB storage you want with the Xbox 360, like this fine selection of 8GB sticks for ~$US20 from NewEgg. Or you could buy the OFFICIAL 8GB flash drive for $US40 from GameStop. Wait.
OK, GameStop says the drive is "pre-configured", though all it takes is a few button presses to configure any drive, for up to 32GB of additional storage. So, um, right!