External hardrive

Do you know of any 1TB external hardrives that power off the USB cable (ie does not need another power source)?

cheers

http://www.ascent.co.nz/productspecification.aspx?ItemID=9385381
plus something from here.
http://www.ascent.co.nz/Category.aspx?majorcatID=18

none of the ones i looked at said they would support 1tb though.. It seems like a waste too with the cost versus 500gig ones, ie more than twice the price for twice as much.