I had numerous ones die, I stopped using them in favor of RE3s, no far, no failures, judge for yourself, try a different model (non-velociraptor) see if your problems go away. Raptor 150s work well if you are looking for 10k SATA drives.
I consolidated from two 150 raptors to one 300GB velociraptor. I hate to have more hard drives clutter my hard drive bay. Might go the RE3 route, or western digital's 640GB drive. Though I hate to give them business. Feel a little irked.