Cavalry CAXB 1TB USB 2.0 / eSATA - 7200RPM 16MB Cache External Hard Drive - CAXB3701T0 $75.99 AR shipped @ Buy.com

Linkavalry

Features
1 TB 7200 RPM 16 MB Cache 3.5" SATA II Hitachi hard disk drive inside
Plug & Play for Windows 2000/XP/Vista (Preformatted to NTFS)
Transfer rate of up to 3.0Gbps (eSATA) or 480Mbps (USB 2.0)
Hard drive activity LED
Aluminum case

Tech Specs
Specifications
USB 2.0 & eSATA interface
Dimensions: 7.8 x 4.5 x 1.3
Weight: 3.5 lbS

Package Includes
1 TB (7200 RPM 16 MB Cache Hitachi Drive) 3.5" hard drive inside an aluminum USB 2.0 enclosure
USB 2.0 cable
Stand
Power adaptor
Resources CD

Systems Requirements
USB port or eSATA port
Windows 2000/ XP/Vista or Mac 9.x and newer

rebate form

Just picked up one of the 1TB WD Green drives for $75 and a Rosewill USB/E-Sata enclosure for $40 at the egg.
Itll be my 2nd one, got a WD Black w/5 year warranty in one and now this Green with 3 yr warranty.
Pretty decent speed for E-Sata and so far so good for reliability.
Still for $75.99 AR, this is a pretty decent deal. Id check into the warranty and how easy it is to open the cavalry enclosure and decide if you want to make your own or go the prepackaged route.