Jeff Buckley's haunting rendition on his 1996 release "Grace". The song is a bit depressing, but there's not a better sit-in-your-car-after-a-long-day-and-look-at-the-moon-and-drive song, ever. You've got to listen to it when you're in the right mood or else you'll miss the greatness.
Anyway, here's a link to a vast collection of "Hallelujah" with renditions by Buckley, Sheryl Crow, Imogen Heap, Bono and Bob Dylan, just to name a few. Check it out and enjoy!!
Special thanks to my man Keith and www.bagofnothing.com for the list. You the man, Keith (and you have one of the funniest and most interesting sites I've seen in a while)!!