Given the increased use of these two materials in high-end car construction, I thought I'd share this video. It's a great comparison and goes to show how strong CF really is, especially when it comes to impact compression (dropping dumbbells).
I don't know the exact weight between these two frames, but usually AL bike frames of the same design are about 1 lb heavier than their CF counterparts. Discuss.
Oh, I did not know about the recycling issue. Aluminum is definitely wins that category as it can be reused infinitely. But still I think CF is pretty good for small applications like bikes because it can be fixed if broken, and will last a long time.