Well, I have to agree with the rest of the girls, do one party but i would single out the kids.  Maybe do one cake for the twins because they are little and they can still share and cake and do a separate cake for your older daughter.  I main reason is because it will be so much better for YOU.  Don't drive yourself crazy doing two parties, One is hard enough!!!  Good luck, let us know what you decide to do.

I think that while they are still young do a combined party I bet your friends and relatives will appreciate it! You will have plenty of time for each to have their own parties.

Well I would find a neutral theme and throw one big party.  You could have a beach theme!!  I have a friend who's 5 and three year old have b-days a week apart and their last combined party was cowboy/cowgirl.  It was very cute.  They got special new boots for the party.  Autumn's were pink.  It was darling.  They have also had separate parties - but only about half of family and friends came to the first one and the other half of family anf friends could make it to the second one....  Good luck!!!

Are you still going to Southwest?  Sat night?

Wow....I've been thinking about this one! I think because they are still young I would try and do one big party and have the theme be boy/girl. As you know when they get older you'll probably have to do three separate ones!!!! It also depends if your family and friends are traveling from out of town? Good luck!