Wow...no mentions of Tahoe. You specifically mentioned "Romantic." A nighttime dinner cruise across Lake Tahoe, surrounded by the mountains, isn't romantic? You can choose a fancy hotel at South Lake, or do the Ritz at Northstar. Getting a blankie put over your lap on the Ritz lift is quite nice, any girl would love. And tons of mountains within minutes of each other.
I do Vermont every weekend. Stowe is your best bet, and they have so much snow they'll be open until April 21st this year (we're going next week). It's spendy, but they have beautiful inns and hotels (stay on the mountain at Spruce Peak if you can afford it). Stowe isn't a mountain (the actual mountains is Mt. Mansfield), it is a town. A long strip of nice restaurants, shopping and stuff to do. And one of the best mountains in Vermont...the only better is probably Jay Peak, which just opened an unbelievable new resort with a kick-ass indoor water park featured on The Travel Channel. Included with your room/lift ticket. But Jay Peak is in the middle of nowhere. That actually makes it more romantic. You can even drive up to Canada in just a short time, and ski Sutton and hang out in the beautiful little town up there.