That's a great age for science experiment type things...books and kits for kitchen experiments. If you don't live somewhere with major winter (I do, so I usually put this out of my mind for winter gifts)...backyard adventure type things...bug house, binoculars, etc.
Maybe his or her own little cookbook and cooking tools?
Ooh! Magic kit? Do they still make those? My brother had one at that age and LOOOVED it!
More complicated building sets---some of the Quadrilla marble runs and erector-set type things (maybe there's a natural toy version? I haven't got to that state with DS yet so I'm fuzzy).
More complex puzzles and games.
Materials for a project to work on together depending on what interests s/he has.
An experience. One on one time with a parent at a cool big-kid experience like a nice show or ice skating or a sporting event, etc.
ps. Remind me of this when DS is that age and I can't think of anything.
