Choosing A Knife
The multi-bladed type knifes ('Swiss army knife') can be useful, but if you only have a single knife you will need something stronger with a general purpose blade.
You can buy some knives that have a compass built into the handle, or have the handle hollowed out so that you can carry equipment inside it. However I would consider this a waste of money. The compass will eventually lose its accuracy after the knife has been used (especially if you use it on hardwoods), and the hollow handle will soon break with use.
The only two general purpose knives I would recommend are a decent folding knife, and a strong 'handled' knife (err, that is a poor name of my own choosing. I wasn't sure how to explain it. I just mean an 'ordinary' knife).
As far as the blade goes, for scouting purposes I would steer clear of the ones on the market that boast several different edges over the length of the blade (serrated, skinning, saw etc. The 'survival' type knifes). I would simply opt for a knife with a good clean edge, that perhaps does have different levels of fineness to the edge along the length of the blade.