Black Tie Optional Attire

My boyfriend and I will be attending a New Year's Eve ball, where the dress is black tie optional / obligatory suit and tie. Since he owns a tux (he is a classical musician), he will be donning his costume penguin for the ball. Her mother, who will be present and wanted to know if I'm wearing a long dress or short. I can not decide! I feel like I should wear a long dress, since he wears a tuxedo, I'm not sold on the dress I own that still corresponds. But there is no long dresses in department stores! It would be easier to find a short dress, but I feel like I should go long, especially since I told his mother, I probably would wear one. Any thoughts?

I would go with the classic LBD, or a chic fashion this season, a jewel toned dress! Long or Short is not important, as it is not shorter than knee length for a formal occation. :)

go long, if you go short, you'll be a liar ... and that I bet you look good in the one you already have, so why spend money on the dress is nails or get nice shoes.

Try a better store.
Get something long and flowy, tight around your stomach and chest, which flows past the waist. Long-backed securities (dipping) with straps on top.

Moo Moo and thongs - have a good time, gurl

probably longer, because it seems more formal, but you can always wear a short dress.

I do not know your budget but here are some gowns in a large if prices (=

http://www.bluefly.com/Badgley-Mischka-P ...
http://www.bluefly.com/Badgley-Mischka-P ...
http://www.bluefly.com/Nicole-Miller-bla ...
http://www1.macys.com/catalog/product/in ...

Go along its more classier. Or you could do something thats between the knees or slightly exceeded.
Here are some ideas for dresses, you could buy that are cheap and very elegant.

I was stuck between too wearing a long dress or a gown for a black tie event yesterday

I ended up wearing a long dress just because it is a black event, I felt as if I'm going to be outdone, if I do not, thank you and God, I did not like it Oscars, everyone comes to their right foot, and I found myself in an Elie Saab Couture gown from the spring of 2008 instead of wearing Chanel dress ..