Yeah, some wet/dry. Grit depends on whatever pieces I have lying around, but generally, 80, 120, and 200. That should cover the basics when out in the field.

Somebody made a Altoids sandpaper/mousepad sharpening kit. I'll try and find pics, but it's basically a section of mousepad glued on top of the lid of an altoids tin, with the sandpaper inside. You wrap the sandpaper around the lid and close it and it holds the sandpaper down.