The hard drive I chose is the Western Digital WD1200JB 120GB hard drive, OEM version. It's an amazingly quiet and fast hard drive. I purchased the OEM version (so called "white box") of the hard drive because it's cheaper. The OEM version does not include mounting brackets, but the Antec KS-282 computer case I'm using doesn't need them. It also does not include mounting screws, which I do need, but these are easy to obtain from Radio Shack.
Here is typical OEM packaging. Bubble wrap with the hard drive sealed in an antistatic bag.
Here are front and rear shots of the hard drive, plus a picture of the mounting screws for the hard drive. The Western Digital WD1200JB hard drive, like most hard drives, has 6 places for screws, three on each side. A total of six round-head machine screws, size 6-32, length 1/4 inch are needed. And, of course, a flathead screwdriver is needed as well. You can pick up a variety pack of screws that will more than you need at a place like Radio Shack.
Data Lifeguard. This utility is available for free on Western Digital's Software Library Download page. It's used to certify the integrity of Western Digital hard drives. Although it's not absolutely necessary to use the Data Lifeguard utility as part of the hard drive install, it's certainly a good idea. After all, we're talking about the integrity of the data on the computer! The ideal time to use Data Lifeguard is now, while the computer is being built, and prior to it's having anything valuable on it, so that the full battery of tests can be run, including the ones that write data. However even the read-only tests are worthwhile. The download will end up creating Data Lifeguard on a floppy disk.
To find a similar utility for a hard drive made by a different manufacturer, check the My Super PC - Hard Drive page for reference links.