I will be buying one of those external drives for a PC (at least 40GB capacity) to use as backup for all my computers.

I was just wondering if there were any recommendations? Which are considered to be the best drives?

Thank you.

I like seagate...... I have a 300GB external that automatically does nightly backups.

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

Seagate it is.

Chris, you can set it up to do backups on its own? Do you mind linking to an image of the hard drive that you own?

Thank you guys.

I use my iPod as my external HD - 20GB, Firewire and it plays MP3s!

But it's not 300GB...I would recommend Seagate, there are also some drive enclosures that you can buy and then swap out the hard drive by simply opening it up, and placing a new hard drive in it - standard hard drive works in it. My buddy did this, saved him a couple bills on total hardware costs and is able to easily upgrade the hard drive when he needs to.

Yeah, that is a very good point.