While I love getting gift cards, go direct to the source. The gift cards you buy at supermarkets are a complete rip off! By the time you pay activation fees etc etc, you've given the card companies a ton of money for nothing. Believe me, I'm in retail and I know. That little gift card "mall" at Safeway? Highest profit spot per square foot of the entire store.
I love Karen's idea of nesting bowls. I got some when I first moved out and have them to this day. Make sure they are tempered glass and can take heat. A good pan is always useful. Cooks Illustrated is a fantastic magazine that I keep for years and years for instuctions and tips. She will love whatever you get her. Happy Holidays!