I'm just getting started with digital audio production. I have a current iMac with 2 USB 2.0 and 2 Firewire 400 ports. I need an external hard drive and am very tempted by this Lacie 500GB USB drive, but I'm concerned that as I adopt more equipment such as midi interface, general audio interface/external "soundcard", etc, I'll end up unduly consuming my USB bandwidth while not benefiting as I should from FW's capabilities. Basically, is you external hd a good way to use up an USB port, or is it the place to use FW 400 given the options available with my iMac? I know FW is smoother, faster interface. Where should one put these advantages to use first?