Blocks, building forts, roll playing games, puzzles, etc. It is proven that at that age, its far more educational for kids to play with simple non electronic toys that encourage the imagination and active play, rather then staring at a screen and hitting buttons when it tells them to or watching some blinky flashy thing spin in circles. It encourages a higher level of brain stimulation and teaches independent thought, which can be used for more educational aspects when they are at school age, it also teaches them alternate methods of entertainment so they dont get addicted to tv and video games.

none, ” must haves “, stuff from nature will show her a lot

Children really don’t need electronic tools to learn letters, addition, etc. at that age. They need to work on social skills and motor skills. Stacking blocks, dress-up, play kitchens, puzzles (lots of puzzles) coloring books, play doh, board games, like Ravensburger makes amazing games – Snails Paced Race is a family favorite.

The best interactive tools I have used are:
iPad – how I wish I had money to buy these, they are AMAZING for young children and adults alike.
Tag Books – make sure you get the pen that has a higher memory, I really like the interactive maps and the phonics books.
Leapster Explorer – my 2 year old is constantly stealing this from her brothers, all of my children love this – however, I’d buy the Leap Pad now that it’s out, but I don’t have personal experience with it. (Downside, there is a lot of buy this, have your parents get this going on with this device.)

If you hate the constant advertising on the Explorer, the MobiGo is a decent alternative, but I don’t like it quite as much. The games don’t seem to be as well done, and the keyboard feature is a bit frustrating for the kids.