iDVD. There really is no substitute for the price. You can still get iLife at Amazon that includes iDVD, but they won't last forever.
iDVD is part of the retail iLife suite and not available separately - it is well worth burying it.
You do not need IMovie for idvd, but you do need to have your videos in .mov format to be able to drop them into iDVD.
And iDVD is compatible with lion, I am using it.