I purchased a very reasonably priced Western Digital My Passport 2TB drive the other day. I thought I'd be terribly clever and extract the drive and implant it into my laptop. WD outsmarted me though and have the USB3 interface on the drives interface card. It's not just an SATA drive with an adaptor. So back into it's case it went and I just relocated portions of my iTunes library to it rather than increasing my laptops size.
The case came apart easily enough though. Yielded without incident or any tab breakage to my selection of spudgers. It snapped back together just like new after sharing it's interface secrets.
Even though I wasn't able to get it into my laptop I am still happy with this. The fact that there is no extra card in there for the interface means that the case is as tiny as possible. The speed of the disk is also impressive for an external, even compared to the other USB3 drive I've got which is a seagate free agent goflex. Which I also like since the sata interface is a separate dongle and you can pop it onto any sata desktop drive. (though there are no provisions for external power so you can't connect it to a full sized drive.)