I'm not sure where the weights before or after normal training argument is these days, but I always do cross training and weights after I run. I don't do really heavy lifting, so technique during lifting after running isn't as difficult for me. In contrast, if I run after I lift, I have to spend the next 45+ minutes managing running technique in a weakened state. Coincidentally, technique often suffers when fatigue sets in. When faced with the choice of intense concentration to maintain proper form or shorten the workout, my decision is to run fresh. It's easier. I guess it would be different if running wasn't the focus or maybe lifting was THE focus for the day. Perhaps I would skip the run and maybe just ride the bike instead if I need to work my vO2.