Take a look at the K2 Fling. My wife has loved hers since she got it and she's definitely not a park rat. She likes riding all mountain and carving. They have it on sale right now through REI for 200.00. The 153 would probably be just right for your significant other. ( my wife has the 149 and is 5'6" and 120lbs)
K2 Fling Snowboard - Women's - '08/'09 at REI.com