Reply to Firewire- for External harddrives or for Soundcards?

I recently got a Macbook pro after one too many frustrating dj experiences on my aged HP. To fully switch over to the Macbook, I need a new external harddrive that works optimally with Mac (my current drive is slow and old) and a soundcard. I am believeing that one of these devices will be a firewire while the other is USB. Which should be which?

Moreover I've got about $250 for the project. Any Suggestions? Must one of the devices be plugged in and not bus powered? So far I'm looking at the Lacie Rugged drive and the Audio 2 DJ. Comments?