I have used Lacie, Iomega, Western Digital, and Maxor external hard drives and I have liked them all. One thing that is helpful in picking out a external hard drive is knowing if it is
NTFS or FAT32 Also there is the decision on RAIDED or mirrored hard drives. Mirrored is just as it sounds the drive is split evenly into 2 parts and are an exact duplicate or the other. Raided is a bit more complex. It is probably better if you google it, because I don't think that my definition would make sense. It makes sense to me but I can't figure out how to write it out.
Google is my friend :)