My vibrate was broken out of the box. I stupidly tried to reflash the ROM (unlocked the bootloader)to solve it if it was software related - it didn't work and I now have to send it in to HTC with unlocked bootloader and hope they take responsibility for the Out Of The Box fault even though I have unlocked my bootloader.
I've read lots and lots and it does seem to be a recurring problem, if not out the box, then after charging and it getting really hot people reporting vibrate has gone.
Dayzee