4.3GB, if it's not 2.5" form factor, you should just chuck it (not worth the trouble and money to convert it). But if you insist, here are some suggestions.
I am going to toot my own horn here, so take it with a grain of salt and do a little more research.
Since you mentioned e-Machine, I will assume this is a 3.5" form factor. Our latest FireXpress 250DX and 350DX (USB 2.0 + FireWire) will be the last external enclosure you will be needing for a while. These are the first units on the market to support any 137GB hard drive, and their FireWire repeaters don't drop daisy-chain.
www.compucable.com
call us and ask for Ben if you have any questions.