That is the trouble... I need a trailer to help me be self sufficient in my newly-car-free lifestyle but I'm really not sure exactly where the dividing line will be between "stuff I'll do on the bike" and "stuff the wife does in her shiny new car". For example this week I have 2 main errands that I can't do by bicycle because I don't have the cargo capacity- pick up a few 12-packs of soda, beer, and seltzer water and picking up a poster I just paid a lot of money to have framed.

I'm leaning towards the 2-wheeled trailers because they seem to be lighter, generally less expensive for the cargo carrying capacity, and the roads I ride on are mostly all quiet neighborhood streets or full-lane road shoulders. (I'm very lucky to live in a pretty "bikable" area.) I've also heard mixed reviews about the knock-off BOB trailers breaking and/or being unstable at even moderate speeds.

Thanks for all the replys and please keep them coming you are all giving me a lot to think about.