One of my favorite overlooked wedding dresses is from Beetle Juice. It is probably overlooked because the wearer is an unwilling child bride (creepy), but it's beautiful just the same. The pointy bangs, the poofy red tulle...it's dated, but still pretty.
It's too bad that there are no good full-length pictures of the dress, but this photo (click to embiggen) shows off the blood-red color of the polka dot lace.
Skip to 2:20 to see the dress; 3:25 to see the ceremony
It looks like a very full skirt (with a hoop skirt underneath?) that stops at her calves. I can't quite see it, but if she's wearing pointy boots, the dress length makes sense. The gown that Geena Davis is wearing is okay too (she's probably the true overlooked bride in this movie), but it's so '80s and not nearly as awesome as Lydia's.