here's the deal I'm currently using 2 lacie big disk extreme 500gb drives for file storage (video, itunes library ect) I have just bought a Lacie 500gb USB drive (the small porche version) as a back up... ...The firewire one's power the disks down when not in use, not that big a deal but it's getting really annoying having to wait 20 seconds for it to power up again if I want to listen to an itunes track after itunes has been idle for a while. The USB one seems to have no lag, it seems to run all the time and is just as quiet as the bigger, slightly older Big Disk Firewire ones. ....now, I can replace my Big Disks with the smaller porche ones, but I can only get the USB ones, what is your opinion? Do I stick with the lag and keep the FW400 or do I go for USB 2.0 and loose the lag? ...is there a big difference between FW400 and USB2.0? thanks.