usb 2.0 external hard drive

i've tried searching through the duc, but i haven't found much information on what i'm looking for. i have an acer aspire 3610 laptop, with no built in firewire. I also have an original MBOX that ihad hooked up to a G4 desktop, but i decided that i didn't use that setup enough to justify having a computer just for recording, so i'd like to use the mbox with this laptop. i installed protools 6.7, and when i try to record using the system drive, it usually ends up giving me errors just a few minutes in the song. so i realized i prolly need an external drive. i was wondering if anybody knew if i could just get away with using a usb 2.0 external drive, or should i buy a PCMCIA firewire card and run a firewire drive? i will probably soon be upgrading laptops to a core 2 duo with built in firewire, but for right now i still need something. i only plan on recording 8-10 tracks or so on the laptop, using a few drum machine prgrams, but mostly live instruments, and then taking the tracks to my friend's to record drums and mix (he has a core 2 duo with all the bells and whistles). any information i can get will be greatly appreciated. btw: system specs: pentium M 1.8 ghz, 512mb ram,, 60 gb system drive, windows XP home (thinking about putting pro on here, but i need to get all my drivers off acer's site first)

Not recommended, but I have been tracking LARGE sessions with a WD MyBook 320gig USB 2.0 drive for over a year now with no issues whatsoever. Actually MIX alot of records that people send me those drives. NO issues at all guys, Doc

Right, but that same drive on another person's system (like mine, for instance, and I've tried the myboook USB drive) may cause buffer errors (which it does for me, my man), which is why they aren't recommended. The problem with USB drives is that because of the USB architecture, they will behave differently on different systems depending upon what else is hooked up, what else the computer is doing, what services are running, how much memory/CPU/throughput is available, what other traffic is on the USB bus, etc etc etc. While a USB drive might work for some (you included, DOC) they will not work for all. Me, I'd rather not gamble, especially if "the perfect take" could be ruined by my choice in hard drives.