M.C.
I have an 8-yr old boy, so not too many suggestions, but Minecraft is all the rage and great for both boys and girls. We are not video gamers at all but Minecraft is actually pretty cool and let's them build worlds from their imaginations. It also takes things down to the basic elements and has them create their worlds by combining these elements (ie. you need flint & steel to make fire).
Also, Grandpa bought him a $50 iTunes gift card when he first received the iPad. I loaded it and password protected it, so when he wants to download an app, he needs my sign-in to approve it. The $50 is still going strong 2 years later!
Finally, they can download books from iTunes too and save them under iBooks. This was great for the airplane and car rides. Hope she enjoys it!