C.C.
Depends how girly she is. If she's pretty girly, you have LOTS of good options - get her a few of those adorable hair bows, or dress-up clothes, or princess ANYTHING. If she is more of a tomboy, how about some of those Polly Pocket cars? My little tomboy about-to-be-4 year old LOVES those. Alternately, every child that age loves coloring books, crayons, markers (washable!), and play-doh. Or, buy her a few Dr. Seuss books.