We cut our hair. Cut our hair real close so you can't see the gray. Seriously, 40 is the new 30. I still have the chops and a lot more wisdom to boot.
I see it going the other way: 40 is the new 50. ;-) A 40-year-old used to be considered mid-level, not senior or particularly wise; certainly not a graybeard.
Totally disagree! I'd also say 30 is the new 20 - especially for me, I'm nearly 28 and have more enthusiasm for things like education and my career than I've ever had.