I've been to the lighting each year I've lived in the D.C. area (all two of them so far) and, although I've never been to the White House Tree lighting, I'd like to think this one is better. If for no other reason than you don't need a ticket. Also, there's some good eating and drinking opportunities just up the Hill.
Here's a picture of last year's tree from Vermont (picture stolen from Sen. Patrick Leahy's Web site):
And here's another one, courtesy of the same place:
Gotta say, this picture almost makes you forget the building in the background is peopled almost entirely by morons. But more on that another day.
Head on out, trust me, you'll have fun. It's a perfect place for a smooch.