I usually have a selection of cards depending on what I'm shooting. If she's going to be shooting sports or somewhere where she'll be taking a lot of pictures on burst, you'll need a faster card. Transcend makes some fast cards at pretty good prices. I've bought have one of their 600x UDMA cards, and I've had no problems with it. I also grabbed one of their 133x as a backup and when I'm doing something like landscapes where I don't need the speed. The Sandisk Extremes are excellent cards. Kingstons I've heard are great cards, but they tend to be a bit overpriced. Another I really like are the Lexar Professional series. I have one of the non-UDMA cards, and I think it's faster than my Transcend. Speaking of which, make sure the camera supports UDMA before you buy one of those cards. I'm almost certain the Nikon 7000 does.
Now, on the other end, if your wife isn't going to be shooting fast action, a 600x professional card is a bit of overkill. I'd just go with a Transcend, Sandisk or Lexar with a speed around 133x-400x (generally whatever's on sale at New Egg) and call it good.