Any restaraunt from the Glazier Group is awesome. They did the food for my wedding and it was AWESOME !!! My favorite restaraunt from their's is the Strip House but if you can't get in there try the Monkey Bar. The website for the Galzier Group is here:
http://theglaziergroup.com/?cslink=p...ebsite_noncust
Another place that's very romantic is
http://www.oneifbyland.com/?cslink=p...ebsite_noncust
Top of tower is also worth checking out
http://topofthetower.citysearch.com/
So is Candella:
http://www.candelarestaurant.com/
But my advise to you is to stay home on Valentine's day. If you don't have a reservation at a restaraunt by now I'm sure you will not get one at a nice place now. The place you will get a reservation at now is going to be SUPER crowded and you will probably not enjoy it as much as you two should any other night out on the town. I would suggest staying home and cooking your special lady a meal yourself, light some candles and then make out. Come into the city a couple of night later and then go out to any of the restaraunts I've recommended. You'll have a much better time. Hope this helps...