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 thinking 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?

Firewire audio cards blow usb audio cards out of the water. If you have $300 lying around grab a presonus firebox. As far as having an external harddrive goes, do you really need one? Unless you're using wavs or have an ungodly amount of tunes there's really no point--it's easier just to keep them on the laptop harddrive.

+1 with the firewire soundcard, heck if you really want to you can daisy chain a fw soundcard & a fw hard drive!

While I agree that FW is the better protocol, I'd say- on this budget- go with a FW800 (if you have the port) HDD and something like a Maya or the Audio 2/4.
Really depends on how much space you want.
I'd rather let some Apple-Store install a 500GB HDD first, which should leave more than enough room internally for Tracks etc.
The Firebox is excellent, have seen Demo-Units at GuitarCenter for 250$, might be worth a look.
From what I understand you want to mix internally? Then I'd really say go with the Maya44, it does a good job on a budget and is lightyears ahead of the MB-Audio Card (output-level-wise).