All my bikes are steel.

Their frames run 4 to 5 lbs each.

What you put on the frames (especially the wheels) has a lot to do with the final weight of the bike.

And if you've got components and bars you like from the old bike that doesn't fit, the shopping gets easier. Bare frames are pretty affordable, and my LBS (bunch of enablers) told me it would be less than $200 to switch parts from one frame to another. Except I've got this cockamamie idea of spending the dark winter days building a bike myself... and I already have too many bikes.

FWIW: Aluminum gives me road buzz, and the carbon I tried felt "dead" and creepy. Try every material, every style, every brand. Ride lots! You never know what you'll discover.