If you are a racer, the weight of your bike is one of your psych weapons. You hang in the parking lot, picking one another's bikes up, and if you have a light one, the guy next to you will remember when you are both suffering on a climb. If you are close to matched, he may just crack thinking about your light bike.
I ain't psychin' anyone anymore, and I can ride anything that won't crumble under me. I like steel, I think, best. Titanium is a very close second. But it is a tempest in a tea pot because after the first hundred cranks or so I forget what the heck I'm riding anyway. I have a long term study going to see if I can measure any performance difference in various frame materials. So far there is absolutely no statistical difference, although the bikes have a fairly wide range of weights. I'll probably have it published posthumously, btw, so don't expect anything soon.
The bottom line, I think, is that aerodynamics have such a much larger effect and frame materials are, um, immaterial.
Ride what makes you feel best.
Clouds parting, going for a ride here...