I don't know who it is but she really belts out the line "O night devine" and it seems very high. Amazing.

I've tried versions by
Charlotte Church
Mariah Carey
Faith Hill
Martina McBride
Leann Rimes

But none of those seem to be it.

Who do you suggest I try next?

celine dion's christmas album starts with this song

Crap, I hope it isn't her

Perhaps you should try non-country singers.

Unless she has more than one version, I don't think it was her. Sounded too slow.

<embed width="425" height="350" src="http://www.youtube.com/v/JDb4EiYu3dY" type="application/x-shockwave-flash" wmode="transparent"></embed>

Dream Theater did a version of it, and I suppose someone could mistake the vocals for being female. Definitely wails away on those high notes...

My wife believes I may be thinking of Amy Grant. I'll have to check that out. I try Dream Theater as well. Didn't know they ever sang it. I doubt it is them, but it would still be worth listening to. Thanks.

But I can't find that she ever sang it.

Not Whitney Houston
Not Clay Aiken (long shot )
Not Reba McIntire

Martina McBride, on this CD, perhaps?
http://www.amazon.com/dp/B000000QHU/

I have that one, and am coming to the conclusion that it must be the one. Certainly the best of the ones I have sampled.

Kelly Clarkson has a great accapella version of this song on the American Idol Holiday Classics CD.

did Sarah Brightman release a version?

I don't see a Sarah Brightman version.

Katherine Jenkins from her Second Nature CD?

Of all the O Holy Nights I have, the version that sticks out in my mind the most is by Mahalia Jackson. Recorded in 1968 her version was and still is pretty popular, she belts out the highs like no ones business. Unless you're referring to a more current, modern day recording, circa 2000 or newer, well... then I can't help you.