I don't get to the gym as often as I'd like to (3 day/wk would be ideal). My routine is mostly compound lifts: deadlifts, squats, bench, row, torso twists, etc. I generally lift heavy enough that I'm considerably fatigued by ten reps/set and do about 4 sets. I've been recording weights and reps in an effort to ensure that I'm increasing volume or weight each session.

Contrary to general opinion, I find lifting helps my riding. Usually the day after heavy leg work I find I'm riding harder than I expect (even though I'm consciously thinking about recovery) and climb hills faster than usual. The core strength benefits of deads and squats really help out on the bike and the other exercises help offset some of the imbalances caused by cycling.