There are some classic ideas like:
- Vampire and Vampire Bride.
- Peter Pan and Tinker Bell
- Robin Hood and Maid Marian
- Gangster and Moll
- Cowboy and Cowgirl
Adam and Eve Couple Costume
Some of these costumes can be brought readymade from Amazon. Others are better made. The Adam and Eve costume that you can find online doesn't look that great. The best ones are the ones that are homemade. They usually incorporate fake leaves and vines, fig leafs, and cool makeup. There are some cool designs to get inspiration from. The best, the ones you will see at Cosplay events, and from really enthusiastic couples, usualyl has the women in a bikini with fig leafs covering the top and bottom. The guy will also have fake fig leafs glued on to his shorts.
Here are some cool homemade Adam and Eve designs
http://www.flickr.com/photos/nathaninsandiego/4070385484/
http://www.flickr.com/photos/stevehopson/4037229574/
http://www.flickr.com/photos/kuniochi/1850052217/
Vampire Bride and Dracula
If you want to do something like Vampire Bride and Dracula (or regular Vampire) then I would suggest getting the outfits already made. There are some cool and sexy vampire bride costumes, and really nice gothic vampire costumes.
For guys, the big part of the costume is going to be the makeupe and teeth. If you want to wear the cape, then yeah, you have to get that online. Most guys probably don't own a cape. But you can wear black slacks and a black shirt, or some other appropriate outfit. You will want some cool vampire teeth.
One of my personal favoriate outfits for women is a really good pair of vampire teeth, a gothic corset, and some bite marks.