<< I think what Workin' is trying to tell you is that if you pull your existing hard drive out you will find that it has a proprietary connector - at least, mine does! If you do buy a stock off the shelf hard drive, you will have to rig up a new connector. If you look hard enough, you can find an adapter. >>
Well, any 2.5 inch IDE drive has the same connector, but different manufacturers have different "caddies" for the drives with their own connectors. You can put different drives into the caddies, you just might have to do a little modification. Also, 2.5 inch drives come in 3 different thicknesses - 17mm, 12mm, and I think 9mm or 7.5mm? The stock 760EL uses a 17mm thick drive, so any other 2.5 inch drive will physically fit with a little modification (maybe drill some new mounting holes or pad the caddy with some foam to get everything to line up). You won't have to find any special adapter.
But the 760 series drive controller supposedly has an electrical oddity which makes the thing freak out if your drive has more capacity than 6 GB. I put a 6 GB drive into mine and it works fine.