A lot of the screws used in wood today are square drives, so how 'bout a set of misc bits, square, torx, etc.

Something to sharpen those planes with. If you have never done it, it can be a little tricky, you have to get an edge, then "hook" it a little bit. Once a plane gets dull, it really makes a mess of things.

Re the crescent wrench, how 'bout a six inch for small stuff, and at least a ten inch for larger.

A pair of "waterpump" or channel lock pliers, or maybe some of those new tricky adjustable pliers that Craftsman has.

In addition to the sandpaper, maybe some emerycloth, and some wet-dry sandpaper...