A Compass??! What the hecks a GPS for? The most important thing is to bring some nice swag. I go to the dollar store to get mine. I also keep a large pack of double A's in my car. Definatly bring more than 1 pen. You'd be suprised how often you leave your only pen in the last cache you visited, only to find no pens in the cache your going to. I have a fanny pack where I keep all my stuff, but don't actually wear it, that's so 80's, and this hobby is nerdy enough. As for bug spray, posion ivy block and first aid, I don't bring that stuff, but since I got 6 cases of posion Ivy last year, I think I'll revise that plan. I am actually the poster boy for the worst case scenario as far as geocaching goes, so nevermind this, just listen to Novac and you'll be fine.
Welcome to the hunt.
-Dr. Witty