My external hard drive that I use for data backup has failed.

 

I am looking for a replacement with the following specifications:

 

Primary considerations are Quality & Speed 

Capacity within the 150 to 300GB range (I don't need a lot of space, only using about 10GB now)

USB2 attachment

Only backing up one machine - network not currently needed

Currently only backing up data files once a week, but would consider whole system backup if it was quick & easy

Is one-button backup a worthwhile consideration?