Here are a few of our favourite things:

Definitely fridge magnets. I frequented out local consignment store and probably had a dozen sets - enough to write long messages to the kids each morning, and for them to help create new ones for Daddy in the afternoon (and greetings for expected visitors).

We loved the Leap Frog Word Whammer, but apparently it's now worth it's weight in gold?! There must be a modern equivalent.....
http://www.amazon.com/Leap-Frog-Wha...21_4?ie=UTF8&refRID=1B0M1KXMNK6BAW3RJ7FQ

Easel with whiteboard/ paper roll. Endless large scribble potential. And if you unroll the paper on the floor, you can really go for miles.

Finger paint with pudding. Oh yes, I am serious!

Dry erase marker books, lots of different kinds, with puzzles, hangman, traceable letters and words - whatever you like. Random sample:
http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Dstripbooks&field-keywords=dry+erase+marker+book

"B is for Bulldozer": http://www.amazon.com/Is-Bulldozer-Construction-ABC/dp/0152057749

Oh, have fun! Such a cool age.