I can offer some help and personal stories on this since I currently own 4 external harddrives and have used each quite extensively.
Seagate Expansion drive - This one fell apart after a year. First it was the connectors that broke, I decided to open it up and stick the drive into an external case. I was actually advised this by a rep at Seagate who said they'd make a note on my serial number (or something, idk how it worked..) that if the drive needed assistance in the future, they would help me even though it was removed from the case. Long story short, it died 4 months later and the RMA procedure was annoying but worked out and I received another drive that is working for 1+ years (knock on wood), I'm always paranoid about it though.
Seagate Goflex 1tb - I bought this during the drought of HDs, when everything was expensive and this was the only deal out there. Has awful reviews but works fine so far. I noticed a scan of the drive locates a few invalid sectors which is worrying.
x2 Western Digital 2TB Elements drives - I love the look of these, just seems to have much better build quality than the Seagate drives and have worked well so far. One is 2 years old the other is almost a year old. Used very infrequently. I have two friends that bought Passport drives, one had it break down completely within a year and the other friend's drive works fine but I needed to use a repair tool online to fix it up since the computer stopped reading it after a while.
I would say go with Western Digital but anything can happen, perhaps go for the best deal in your area. Hope this was helpful.
