External Hard drive and Peer to Peer ???

Hi Friends, I have never owned an external hard drive but I am planning to get one in a few days. I basically want to use it to download movies and softwares from Peer to Peer networks , that means my external hard disc will be On 10 to 12 hours a day.
I have been using peer to peer sharing on my laptop for years and I have never had any problems.....but in various reviews people have said that external hard disc crashes easily....
Can any body please shed some light on it and tell me what difference will it make if I use an ecternal hard drive to store the data on from a Peer to Peer sharing network.....Are External Hard Drive reliable??? Are they worth spending money on?? My boggest cocern is that they may crash??
Please help.
I am thinking of buying Western Digital My book Hard drive

 

the premade hard drives are nice, but if you're using the external mostly for downloading stuff onto, and leaving it on for long periods of time, you might be better off making your own external. It's cheaper and you can select better components on the whole. All you have to do is get a hard drive and a hd enclosure, plug it in, format and you're set.