Suitable external harddrive size

[J1mmy]

Im planning to purchase a Western Digital My Book.

My choice is either between the 320GB version and 500GB verison, Im not going for the firewire version becasue its an extra £20 and Im only going to be using it for storage, USB2 is more than enough for me.

Im not sure which one to go for, im tempted to go for the 500GB just becasue its a larger space but then theres loads of cons that come with it too. It usually gets slower when approaching its maximum capacity, and if something was to happen, I would have lost 500GB of data! These are the kind of thoughts holding me back, at least is isnt too bad with teh 320GB version.

So i need some help deciding on this...

[BluesMan1]

Always keep in mind that you may have more stuff in the future. I have my important stuff on my computer, i also have backups on an external HD and another backup on DVD's so i can get everything back if all my drives failed

It's maybe not the best way to do it but it works for me so having a 320 or a 500 is the same because losing 320 or losing 500 is about as painful for either one or the other