I'm using one of THESE. It works very well, and even though it's kind of pokey-slow (USB 2.0 only, would have preferred FW400/800) I got it for $75 out-the-door so I can't complain too loudly.
I finally decided to go with the OWC Mercury Elite-AL Pro drive. Really like the look of it, trust OWC anyway, and it should keep me covered in the future with eSATA.
2 WD MyBook Pros! I bought a 250gb a few months back and another 500gb just recently. I just can't get enough of their cool silver book design. Just makes you wanna buy more and more so you can build a "hdd library" on your book shelf.
I've got an Iomega 640Gb Ultramax with Firewire 800 at home, and am considering my options for portable use at the moment. Have to say the 250Gb WD Passport is looking good at £95 from Amazon UK.