First of all, I wanted to thank you all for your help on my last post regarding this. Here is the update.
1) These cotton petti-pants arrived. They are comfortable and worked well. But, I don't know if I need order a smaller size, or if it is just the cut. But, they just don't hang as cutely on me as they do on the model. In the picture they hang in kind of a classic boudoir sexy. On me, they looked like a pair of grandma bloomers. But, they kept my legs from sticking together and they were soft and comfy. They will hang out in my under dress rotation.
2) The Jockey shorts LaVieBohemeB recommended are just as amazing as she endorsed (though I've only been wearing them an hour). They are tight enough to not wrinkle, but loose enough that I'm not afraid they are going to ride up and start giving me perma-wedgie. I ordered them in bright pink, because when given the option of colors, I'm always going to choose bright pink. It works fine under most of my clothes (due to that color option rule), but I'll probably order some in black or grey for certain dressier occassions.
I have a couple concerns, like the tight and nylon might make things get a little sweaty down there. But, I guess in this heat, everything does. I'm also a little concerned that the fabric might cause things to ride up a little. I guess I'll just have to wait and see.
3) The only problem with both of these options is that they aren't sexy. I don't think they are enough to stop my boyfriend if he wants what's under my dress. However, on special occasions I would like something a little prettier, so after my next paycheck, I think I'm going to order these Bandelettes. I'm not sure they are quite wide enough the prevent chafing. But, if they don't work, I can just return them.
Thanks for the advice and help. I do highly recommend at least giving the Jockey shorts a try. They seem to be working great so far.