an Orinoco "popsicle" stick antenna. White 6inch tall plastic thing. I've slapped a strong magnet to the bottom and it works well. since I'm simply stumbling and not trying to access an AP from a distance an Omni makes the most sense - no reason to skew my data to the direction the antenna is pointing.

Good tip on th eOmni's though. I'd not considered it but yeah I gues pointing it at yourself wouldn't be too smart. I've yet to build one or have reason to but I appreciate the warning!