Me personally would take her out to a nice dinner and perhaps a movie. Women tend to care more about what your personality is like rather than anything else, so I would keep it simple.
The flower idea is so played out today. Save the cash for your dinner with a nice bottle of wine.
Since I know you are nothing like me (in a good way

), keep the converstaion real and to the point. You should come out ahead if you go this route.
