I think you should listen to your feelings. If you like Danielle, talk to her about your feelings or ask her out. I don't think you'll be happy if you go for Brittany. Well, you might have much better chances with her, but if you are so close to Danielle, maybe it will last longer. On the other hand, you have to very careful not to destroy your friendship..
NearokA, don't you have any female friends? It doesn't really sound like that. Of course friendship is good.. (not compared to dating to girl of course, but better than not being with her at all!)