I have traveled and lived in many places across the US. CO is nice. But it highly depends on what you are willing to pay and put up with. The four seasons in CO is tough to find though(you have winter, a short spring - also called "mud season" in the higher elevations, medium summer, and a short fall). I would rule out Denver. Housing costs have gone up quite a bit - almost comparable to living in the high country(near the ski areas). Traffic sucks in Denver too. CA is probably out just due to home prices. If your husband is in the medical field, I know that Ann Arbor, Grand Rapids and Lansing Michigan are three prime spots for those in the field. GR and Lansing are affordable, with Ann Arbor being the higher of the three. Ann Arbor has the University of Michigan and Lansing has Michigan State University. Both towns are very culturally diverse(due to the colleges). We have a solid 4 seasons here as well. The state is beautiful, especially as you go further north. Home prices are near the lower end of the national average. You can buy a much larger home for less money if that is what you are looking to do. The only "hoods" I can think of are found in the core of Flint and Detroit proper. People are very friendly.
Like I said, I've lived in many different places and traveled to many, many more. I am proud to call MI home now.
<----- **oh, and my avatar pic was taken from the beach on Lake Michigan --- clean water you can swim in!)**