Need a good desktop external hdd

[Nocky24]

Just went to buy one and didnt realise how many there are. Looking for one about 500GB and will be moved about backing up data for a laptop and 2 pcs at home. Are they all pretty much the same or are there any particular makes to preference with external hdds? Budgets around £60

Thanks

 

[Hathaway]

I'm after the Samsung S2, which is tiny has no need for an AC adapter (USB powered) which means less hassle if being moved about quite a bit, and I've found it online at £60 (500gb version).
Unfortunately overclockers doesn't seem to sell them... yet?