Hmmm, I've been thinking about cycling friendly communities from a slightly different viewpoint. I'd like to be able to access many/most of dail needs by cycling (and walking) in addition to having great recreational road and off-road riding. So in addition to an acceptable community cycling infrastructure:
1. Reasonable housing costs (say median detached single family home price no more than $300k)
2. Local economy not dominated by one industry (don't want to pick on tourism, but definitely don't want an economy dependent on tourists)
3. Stratified population demographics
4. Middle-of-the-road politics (though I'm not sure this exists any more)
The list is incomplete but I'm not sure there's any place in the USA that meets them. My personal experience is limited, but as for cycling infrastructure and cycling in general, I can comment on several places. The area around Northampton, MA seems nice as it has a lot of colleges in the area and plenty of routes for road cycling. The youthful population of college towns seems to go with cycling. Memphis isn't great and I own property near the Natchez Trace Parkway in Mississippi which has pretty good rural riding but there's not much of an economy there. Anchorage, Alaska is almost completely accessible by bike, at least during the summer months. I've visited and biked around suburban Austin and enjoyed the riding but not really knowledgeable about the greater landscape there. Bend, Oregon seems to have a lot to offer for cyclists, especially if you like hills but, again, my knowledge is limited due to my short stay there.
I'm interested in seeing what other respondents to this thread have to offer for locations.