This HDD offers USB 3.0 and receives a 4 out of 5 star rating from TR. The main downside is the relatively high price tag for its capacity.
"At just 9mm high the Seagate GoFlex Slim is currently the world's thinnest portable hard drive - it's 38 per cent slimmer than the current GoFlex ultra-portable drives.
This 7200 RPM drive is USB 3.0 compatible (backwards compatible with USB 2.0), so you benefit from fast transfers if your PC or Mac has a USB 3.0 port. You can also connect the GoFlex via SATA once you've unplugged the USB adaptor. Should you want to connect the drive via FireWire or eSATA, you can buy separate adaptors."