Raptors have a higher than normal failure rate among hard drives. IMO, SSD aren't quite there yet. And to get a decent one you gotta shell out some cash. Tomshardware.com has some hard drive benchmarks. I'd favor drives with 5 year warranties over the 3 year types.
The philosophy I have behind hard drive is not "if it will fail," but more of "when will it fail." Knock on wood, in the last 13 years, I've suffered one hard drive failure on my main computer. And that was circa 1997. I generally do not like to keep hard drives in service for more than 3 years. At least on my main rig. Frequent back ups multiple times a year on various types of media is always important. Don't be one of those people that rely only on an external hard drive as a back-up means, its still a hard drive and it will eventually fail (either the drive fails).
Check reviews, benchmarks and prices. You'll find the best one. Personally, I've use Maxtor and now Seagate drive for 10 years. After they've met their service life in my main computer, they either become hand me downs for friends/relatives or in server boxes. I've got a 9 year old Maxtor 6.5gb in a linux box right now.