Wow, I thought the 500GB Cavalry drive for $79.99 was a good deal, but now comes the Vox V1 750GB external eSATA/USB drive for $99. That's an after-rebate price that doesn't include shipping (about $11), but it's still an amazing deal.
The Vox V1 can connect to either an external SATA or USB 2.0 port. CNET reviewed it with the latter and called it "the fastest USB 2.0 external hard drive we've ever tested." If your machine happens to have an eSATA port, the 7,200-rpm drive has the potential for even faster throughput. (Indeed, it would be about on par with your internal SATA drive.)
CNET didn't like the bundled backup utility, though obviously you can use the drive without it. (I recommend the freeware Comodo Backup if you just want to archive your data.) The drive itself is new, not a refurb, so you get the full one-year manufacturer's warranty. The $35 mail-in rebate offer expires May 23.