my daughter will be 4 in January too. We got her a kid digital camera, found a fisher price one for 35.00 on ebay. She constantly wants to use mine so i figure she'll love it. My mom is going to get her a sansa shaker, which is a kid MP3 player with big buttons, easy to hold, and load with music. I think it was on sale at Toys r us for 20.00? She also loves to draw so we got her some art supplies. I want to get her some dress up clothes/shoes so she'll stop wearing mine. I'm going to look for clearance princess outfits/shoes after halloween.
Since all but the princess outfits are pretty gender neutral of course that could be changes to pirate outfits, superheros and such I thought I'd share. Good luck!