All externals come pre-formatted in FAT-32, which you don't want. You need to convert to NTFS.
Second, you don't want FW400 or USB, unless it is for backup purposes only.
The only externals suitable for editing work are NTFS formatted and use an eSATA or possibly a FW800 interface (the lesser of the two performance wise).
Thank you, is there one you recommend?
And how do you re-format?
I agree completely with Harm.
Because Mac's cannot PC externals, in NTSF, most mfgrs. pre-format to FAT-32, so they can be read by either Mac's, or PC's. The trouble with FAT-32 is that there is an ~ 4GB file size limit, and they are slower at doing reads/wirtes, than will be an NTSF.
I have tried to edit to/from with USB 2.0's and FW-400's. Both are too slow, IMHO, and the USB 2.0s' suffered from read/write failures, when data streams, like from an editing program, are involved. It was not until FW-800's, that I could finally edit to/from, and with safety. The eSATA disks are even better, but I am heavily invested in FW-800's, so have not upgraded to eSATA yet. Next machines will have both.
As for a rec., I have a bunch of Maxtors (now Seagate), but all are in the 1.5 - 2TB range. I also have some Western Digital units, from 500GB to 2TB in size. Over the years, I have had only one of these fail, and I think that I got a "return" unit, packaged by up as new by Fry's Electronics - too late to return it, when it failed.
I'd look at the Western Digital Store, and find a unit that is within your size range. Note: they do several levels of externals, that rather look and sound alike, but the "World Edition" units offer multiple connections, and are usually FW-400 & FW-800 (often called IEEE-1394, sometimes 1394a, and IEEE-1394b), and often eSATA as well.
Do not know if they offer "educational discounts," but I would inquire.