The Eternal Hallelujah

Hallelujah.
I first heard the song on either Crossing Jordan or Without A Trace.

Some relevant links I recently found:

Via popurls then digg and also MeFi.

An article on the song's background and use. (Also at archives.)

At YouTube:

Jeff Buckley's version.
(OR Search YouTube.)
On Crossing Jordan Epi 113, Miracles & Wonders.
This is the version I like the best - the studio version.

Norwegian guys singing the song. (Espen Lind, Askil Holm, Alejandro Fuentes, and Kurt Nilsen)

John Cale's version used on the show Scrubs and in the movie, Shrek. (OR Search YouTube.)

Rufus Wainwright's version used on Without A Trace Fallout episode and the Shrek Soundtrack.

K.D. Lang's version is also popular.

Leonard Cohen's version (songwriter).

Imogen Heap's version
(This one played on The O.C. - Marissa Cooper's death.)

More Links:

Songfacts
Wiki