Just out of interest, I've had several HD failures - the majority of which are probably just to do with bad luck.
I recently got another seagate drive (purely by accident - I hate seagate now) and used it as a purely external bittorrent storage device.
250GB of purely legal content later (don't ask) I have a massive failure.
Could the number of read/write opperations performed by bittorrent be responsible for aging the drive?