TN has no income taxes but it does snow in Knoxville. The south has that humidity and those daily afternoon thunderstorms. It's dryer and arid out west but AZ/PHX is stifling during the summer heat. Vegas is also too hot. If you can afford it, I would settle halfway between Phoenix and Flagstaff...like Prescott or Sedona.

 

Texas- No state income tax. But for all year riding stick to southern part of the state. That is as long as hot summers dont bother you.

 

I would not rule out the Texas Hill Country - like Kerrville. Western Austin would work as well.

 

I've lived all over the country, I grew up in Florida btw. My favorite place is where we live now, the Shenandoah Valley in Virginia. Great riding, 4 seasons, winter is relatively brief usually over by April, access to great medical care, and a few hours from DC if you want to go sight seeing. The Asheville, NC area is great also but too much snow in the winter to live there year around. I like mountains and twisty roads so I would never live in flatlands no matter how warm or sunny, lol. I can go to Bikeweek every year if I want to enjoy the concrete jungle.

 

Based on the OP's criteria, I'd say Eastern San Diego County, or Western Imperial County. (They both get kinda hot during summertime tho. It's a "dry" heat, ya know!) 12 month riding season, mountains are very close for summer riding, and have awesome motorcycle roads. Right now, today, in the desert, you could be riding your bike. it's a chilly 50F as I type this (dawn), with a high of 71F today. The wind is blowing a solid 2kts. Ride 85 to 100 miles West, and you're cruising the beach in Sandy Eggo. Oh, one other thing about Sandy Eggo....craft beer.
So, let's see...
10-12 month riding season? Check.
Cheap housing? Check. (Imperial County.)
"Not the same place every ride?" Check.
4 different riding climates within 100 miles? Check.
Julian pie? Check.
Empty roads? Check. (As long as you ride "where they aren't.")
Roads in great shape? Check.
Minimal debris on the roads? Check
Literally thousands of miles of awesome motorcycle roads that are empty.
Here's a couple pics for example...

 

Look at Alabama especially the central and north parts of the state. It has some nice areas to ride and its close to Western NC and Tenn if your into the Tail of the Dragon thing.http://www.motorcycleroads.com/Routes/Alabama_76.html

 

If I were moving and my criteria was for riding only, I have to take a good look at western North Carolina.

 

I went through a lengthy process to determine where I would retire for both economic reasons and riding reasons. Initially we looked at NV, FL and TX we wanted somewhere warm, little to no state taxes and a lower cost of living. We settled on Texas, then where? We looked at historic weather patterns, average temperatures and cost of living. Initially we looked at the areas outside of Austin, although much cheaper than California, we found that the housing prices were cheaper yet in San Antonio, we chose SA. We couldn't be happier, we are close to the hill country, the cost of living is very affordable, we have access to some of the greatest medical care available, access to the bases for shopping and the weather is most of the time very pleasant. There is plenty to do and see in SA and we can drive/ride in most any direction and see something interesting...Texas is a big state and has a lot to offer.

 

 

I would also vote for Western NC, or Eastern TN. Roads are challenging, people are nice, housing is relatively inexpensive, as are the tax rates. One thing you may be giving up is getting adjusted to not having everything you need in close proximity to you. The more rural you get the less shopping, restaurants, etc. there are.