Seagate has been an industry leader for Internal and External hard drives. As far as I know, their external drives also have a 5 year warranty return and they are reasonably low-heat drives. I had an old Western Digital Ex-HDD and it gave me alot of trouble with temperature problems, so I took it back.
My advice is that you go for a Seagate, if your budget allows for it!
~Equinox