We have gotten lots and lots of use out of our Little People sets. DD2.75 plays with them daily and my older boys (5 and 7) still play with them.
The boys were never particularly fond of it, but DD loves the Magna Doodle.
DD also loves to string beads, the tiny choking-hazard ones. I give her a plastic needle (I think its called a tapestry needle) and a very long piece of yarn with a big knot at the end and she will string beads for 45min!
She adores stickers and paper, I buy the stickers in the 500 pack sheets and hand them to her with the paper. She loves it even more if I give her markers, crayons and colored pencils, too. Then, if I give her a pair of scissors after the stickers have lost their appeal, she'll sit there for another 20min cutting the paper.