I've recently more-or-less cut out weight training and started running, mostly because I've always sucked at running. Within a few weeks of seriously trying it, I no longer sucked at running and now I'm doing three-mile runs several times a week, and aiming for a marathon (hooray, arbitrary and possibly stupid goals!).
Has anyone tried the gyminee.com startup which was mentioned? It looks very well designed, and I'm thinking of signing up.