I just bought an external Western Digitial 500GB MyBook hard drive that is capable of connecting through either eSATA or USB 2.0.  The drive only comes with a USB cable so I'm stuck using that until I got back to the store tomorrow to purchase a new eSATA cable.  I initially tried copying my source folder over to the drive (~1,8GB), but it was copying slower than I could check it out from SVN over the Internet.  Obviously something was wrong.  The culprit as it turns out was that the drive comes preformatted using FAT32 and I just tried using it as is.  Big mistake!  One NTFS reformat later and my drive is copying like a champ.