I use 10000rpm WD Raptors in raid mode and have never had problems in the last 6 years. In fact between my brother and father and I we have about 9x Raptor drives and none have ever failed.
We've had Maxtor, Seagate, plain Wester Digitals in the past and all have failed after 5 years or so.
So the Raptors are the only drives I can trust. Mind you, I would like to go SSD one day but they are all not created equally. In fact, the slow SSD drives are not much faster than normal HDD's, so make sure you do your research before hand. Cheaper is not always the way to go.