The Western Digital Line is a consumer aimed 10K rpm SATA drive that gives great performance for an equally great price. Upon my new computer build, I decided to splurge and see if the extra 2800 rpms compared with the regular 7200rpm offerings was worth it.
At first, the main thing you'll notice with the drive is it makes more noise than your usual HD. It makes sounds when its 'working' and although not glaringly loud, it may be an issue for those looking for silent or more passively cooled systems. I have a system with low rpm fans in it and the sound doesn't stick out, and I have never had anyone else mention it before.
Load up times are REALLY fast. While whirring away, the hard drive when used as a boot drive, can load up a fresh Windows XP install in about 40 seconds from pushing the power button. This is much faster than my old drive and is a convenient change for me, as I don't leave my computer on as much, as I know I can boot up much quicker. I haven't tested it with newer games, as I know they have to load lots of textures and such from hard drives, but I assume it would help.
Although not on the newer SATAII architecture, the WD Raptor is plenty fast for anyone's needs. With a price tag of around $150 nowadays, if you already have a massive storage drive, consider the Raptor as a bootup option, if you're looking for the best performance. A 5 year warranty is included with the drive, which will definitely last its useful lifetime. You're paying a pretty penny for speed over storage, depending on what you're looking for.