Weights first, then cardio, as stated above. I just wanted to add that I've done it both ways. I remember running back when I wasn't used to it and then bouncing over to my personal trainer all proud of myself. I couldn't lift a thing! It was awful! I was so shaky. He made me promise not to run before seeing him again.
Except when I kill myself, I honestly don't notice a difference though. I actually prefer to do cardio first because I like to lift with a high heart rate. It just feels good. But you can accomplish this by doing jumping jacks between sets too.