Thought I'd post my two cents on two subjects you mentioned - I agree with badgercat - about the natural progression. My husband bought me a mountain bike before we were married. I don't think I rode more than 50 miles over 5 years.

Then I started riding it one spring when the weather was nice enough to be outside, but not nice enough to go to the beach or anything. I started really getting into it - remember the time I rode 30 miles and I beamed for days at my accomplishment.

That fall I bought a 2006 or 07 Trek 7.3 for about $700 I think. I loved my hybrid. Started riding every weekend, usually 40-50 miles at a time. Hills, flats, loved it. Point is, it built my confidence to get me where I am now.

Last weekend I dropped about 2k on a 2010 Cannondale Synapse 5 with a compact double gear in front (see the thread I started about worrying if the compact double would get me up hills). I'm loving it! An adjustment...but, it's working for me. I don't think I would have gotten to the road bike if I didn't have the hybrid in between.

Second point - I have a chronic lower left back problem I was afraid of flaring up with the road bike. Don't know if it's all the core work or just a good fit, but absolutely no problem with the back.