So, combining the ideas from several recent posts, here is a mock-up of how I'll try to do wandering monsters (disregard the little house pictures that's from a previous unrealized idea and I'm just using them because they're business card size).
The page on the right will have the map and most of the info I need will be on the map. Of course some charts will be necessary for magical pools and stuff, but they will only become important when they're fiddled with so they can be put behind the map.
I'll write in numbers beside the cards. If a wandering number is called for I'll roll and the first card in that slot is the encounter. I can have a coupls cards in each slot. I'd like to have a silhouette of the creature on the cards with their hit dice in white. Then a bunch of checkboxes for hitpoints for each creature, tallied xp, etc. If I make the numbers beside the cards correspond to broad categories of probability: common, rare, etc-- then I can just re-use this same sheet for every adventure, just change the cards for what I consider encounters in that place (hmm, it would be good to record which creatures somehow, so if I come back six months later I won't have to remember what cards I'd used, and what I said was common in that dungeon).
Update: Here is what a card will probably look like:
p.s. my computer hasn't crashed in a few days (knock on wood) so maybe I can get back to silhouettes soon.
Update2: No way anyone is going to create unique cards for every batch of creatures, so I put a grid that you can use to outline hp amounts with a marker or pencil after you roll them but before play. (I suppose you might use these little grids to draw a micro lair too if these are wilderness adventures). Anyway, here is an image of a few more silhouettes with grids. I'm using a business card template in OpenOffice and Gimp: