One man's brave is another man's...
I guess you've considered all other alternatives, like doing a spring cleaning of your drive, or trying to offload non-mission-critical info and applications to an external.
Also wondering if your machine is still covered by Applecare. If so, have an apple authorized service provider (3rd party, like Promacs in OKC or Megamacs in Tulsa) supply and install the drive, and keep the freakin' receipt so your warranty isn't voided.
You're going to find all sorts of opinions on this and other forums about 'this drive sucks' or 'this one is great' etc. I've had no problems with the WD scorpio black 320 gig 7200 rpm hard drive. No noise, heat and can't tell a difference vibrationwise between it and the stock fujitsu on my 2.4 MBP (late 08). My advice to buy the drive from a brick and mortar store with a decent return policy (even though it's more money than online) so you can immediately swap it out if you get, God forbid, a lemon.
I'm also presuming you've looked up the specs on something like ifixit.com to review the installation procedure and made sure what kind of connector the drive uses. Good luck!