@halva careful of launch models, i think those are the only ones that can't boot from USB. im not sure if it's a board revision thing or not, but my 4GB one that i bought 2-3 years after launch can boot from USB and my 8GB launch model can't
@halva USB for just storage is fine, the issue comes when you wanna boot from USB. If you're booting from the SD card and have some storage plugged in then you should be fine