Look at the specs of the hard drive for price. RPM, buffer, seek time.... Size doesnt mean everything.
Also eSata works if you have a Sata port on your motherboard...most should have that by now. But USB is always nice to have since everyone has USB.
What I found works for me the best are hard drive with an RJ45 connection. Network cable...
I plug them in to my router and all 3 computers can access it at any time.







