I'm 5'0" 105 and I can feel the difference between a stiff bike and one that is compliant... my old alu bike was slooooooooooow to accelerate once I knew what I was looking for I swear I could feel the energy going into flexing that bottom bracket... It was quite a difference between that and my carbon bike. That said, geometry and construction have as much to do with feel as materials.
I know someone who sold a Ti bike because it was too stiff for her liking and I've known people who've had carbon bikes with no snap. Steel can be a smooth and cushy cadillac ride or can be turned into a swift racer.
P.S. - Ti isn't necessarily a forever frame... I have a teammate (who is not big - not much bigger than me) who has totaled not one but two Ti frames...