On my Dell E6400, my eSATA drive runs at about 95MB/sec...while my USB 2.0 runs around 25MB/sec
I bought one of these;Newegg.com - Thermaltake BlacX ST0005U External Hard Drive SATA Enclosure Docking Station 2.5” & 3.5” USB 2.0 & eSATA
it's $25 after rebate and can use both eSATA and USB. You simply provide the hard drive. It works very well. I've got one at work and at home.