Steel? I don't ride anything else. I rode a Ritchey RB-1 for 10 years, and I'm in my 6th year on my Ritchey Road Logic. My SS MTB is an old Bridgestone MB-3, and my geared MTB is the a '95 Stumpjumper -- the last year they offered a steel one.

I don't have anything against the other frame materials, I just prefer steel. My bikes all weigh a pound more because of it, but they don't hold me back. I like the softness of the frames. I'm a 6'4" sprinter, and full-power sprints feel like dancing on a wood floor -- the return from the flex just takes the edge of the mechanical nature of the machine -- making it feel more organic.

I could see myself enjoying a Ti frame, but I'm too frugal to drop the coin on one. Same with Carbon Fiber, expensive plus I don't like its failure mode. Aluminum just doesn't do it for me: oversized tubing makes them too stiff, and if they weren't stiff, they'd fatigue and crack at the head/top tube or around the bb shell after a few years.

(ripped from the dated, yet classic, Metallurgy for Cyclists)

"Once giants lived in the earth, Conan. And in the darkness of chaos, they fooled Crom, and they took from him the enigma of steel. Crom was angered, and the earth shook. Fire and Wind struck down these giants ... but in their rage, the gods forgot the secret of steel and left it on the battlefield. And we who found it are just men - not gods, not giants, just men. The secret of steel has always carried with it a mystery. You must learn its riddle, Conan. You must learn its discipline. For no one, no one in the world can you trust - not men, not women, not beasts ... this you can trust." - Conan's dad, from the film Conan the Barbarian.