I think running is fine as long as you don't over do it. I run once a week and that's it. I jog about a mile, then do wind sprints (50yards, as many times as I feel up to). Long range running will burn muscle, sprinting/high-intensity cardio for short periods is good at burning fat. Don't believe me, look at a world class sprinters body, much more muscular than that of a distance runner. Anyway, I think the cardio benefits are worthwhile. My goal isn't absolute mass at all cost, so for me this works.
DrG