I've been doing the 5x5 workout routine for the past 6 months or so and I've seen great results. I'm 5 11' and was really skinny at 135lbs. Now I'm weighing in at 151lbs and I feel great but I know I'm still skinny. I'm still not where I want to be. I've noticed that I'm plateauing a bit with the 5x5 program; I'm just not seeing great results anymore as my lifts have stalled.

What's a good program to move onto after 5x5?