I don't know your girlfriend or anything, but personally flowers are great but something a bit more original would be something I would like more. Something like a bonsai tree or a fish. Something that none of her friends boyfriends have done. Try something that isn't too hard to take care of, but something that won't die a few days later like a rose, that way she has something to look at and think of you for a while, instead of a few days.