Steel is a good 'all day ride' type of bike. Like what was said already, not for speed, but for comfort and durability. Of all my road bikes, aluminum, carbon and steel, my steel commuter soaks up the potholes worry free. Yea, it weighs well north of 10 lbs more than my CF road bike as it is built up like a tank for rough commuting chores, but just soaks up the hits.
My last road bike, from the 80s, was Columbus SLX steel and nothing I have tried since can come close to it in comfort; I just wish it were a better fit (too big) or I would still be riding it.
By comparison, my current road bike, a Specialized Ruby Expert, does a good job dampening vibrations, but the larger pothole hits are no where near as deftly handled as they are on steel.
My aluminum Fuji, that I also use for commuting, even with its CF fork, is just horrible by comparison. I put larger 25c tires on it and that made little difference. When I hit something on it, I can feel it vibrate up my hands and posterior. It weighs maybe 4lbs less than the steel commuter, but I almost never ride it because it just rattles my teeth. If I could get really big tires on it (32c or 35c) it would probably help but they won't fit and clear the brakes.
So basically, CF will get the weight down, as low as the $$ you are willing to spend. Aluminum can be a decent ride, weigh a little more, but will transmit those road vibrations. Steel can be anything from a beater commuter bike that weighs 28 lbs unloaded like mine, or can be in the 20lb range if you are willing to spend the $$. If weight vs cost is part of the equation, CF rules. To get anywhere near the weight of a typical CF bike in steel, you will be spending much more and come nowhere close. But the ride will be magic.
Tzvia- rollin' slow...
Specialized Ruby Expert/mens Bontrager Inform RXL
Specialized SWorks Safire/mens Bontrager Inform RL
Giant Anthem-W XT-XTR/mens Bontrager Inform RXL
Fuji Newest 3 commuter/mens Bontrager Inform RL
Novara E.T.A commuter/mens Bontrager Inform RL