Well I have 2 320 GB Western Digital MyBooks and I'd swear by those. One is almost 4 years old, the other only about two, and both are fine. And they've been getting regularly wiped and reformatted and having hugs chunks of data written to them on a regular basis.

I know many other people too who use and abuse MyBooks and say the same things. For what they are, they're probably about the best you can get.

Stay away from Seagate externals though. For that matter stay away from Seagate, period.