I've been a bit out of the hardware game for a few years, and the snowball's really beginning to grow with it's roll (Moore's law). I used to suggest Seagate (they also own Maxtor). They've been the best as far as I know.
Some may suggest LaCie. My personal opinion of LaCie is that they do make a quality product, but you can get the same quality for a much cheaper price.
I'd stay away from Western Digital.
If you're going to use an external disc, buy 2 of them. Make one the primary and use the other as a backup. Store the backup (in a temprature controled environment) when you're not backing up to it.
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