My mom got this for my niece ad she loves it! If you do get it, be sure to get the pump to blow it up. Or an easel is always good, I go my niece the pink crayons one with a dry erase board.
My ds is 2 and he LOVES puzzles right now. The ones he has are pretty simple and say "ages 2 and up". He also loves the Little People sets which I know can be for boys or girls. Or, what about a movie? My ds is starting to have a longer attention span and enjoys Toy Story, Cars, etc. For a girl you could probably find a princess type movie.
My daughter is also 2. She loves books, puzzles, anything Dora the Explorer, Mickey Mouse, mega blocks, play dough, crayons and coloring books, etc. Good luck finding a gift!
I just head to Kohl's and buy the book and stuffed animal that they have on special at the end of their check-out lanes. A donation usually goes to a charity. Always a big hit!
Little People
Fisher Price car sets (they come in girl colors if that matters)
Mega Blocks
Duplos
Coloring
Puzzles
Cozy Coupe
Water Table (more of a summer thing)
Tub Toys
Baby dolls and pushing a stroller
Kitchen set
Books and "reading"
I second the water table or other outdoor toy.
My DD is 3 and used my older DD's water table - the older one is 9. It lasted a long time!
Both of them played with it for hours!
Other ideas: foam hopscotch game, sprinkler toy, pool toys, gardening toys, bathtub toys, books, Play-doh sets.