Sound like you to are find out a lot about each other. I helped a friend with decorating a hotel room for a special night with her boyfriend. It was Valentines Day as well so I think these suggestions might help as well.

We went and got roses, candles, a ballon (had I love you on it), a card and chocolates. I am not sure what she did with the chocolates but hey she said she lots of fun.

I loaned her my blindfold, handcuffs, and flogger. I don't know the details on all of that but she said she had LOTS of fun with those.

I helped with decorating by putting the flowers in a couple different vases and then putting these around the room. Candles accompanied these as well. The card she laid out with the ballon so he would see it when he came into the room.

The main thing here is that she will mostly LOVE the idea you put time and effort into your evening. You don't necessarily have to go all out and expensive. She will love the thought most of all!!