I can speak most intelligently to Texas' large cities, as I spend a lot of time traveling between Houston, Austin and Dallas. Back in 2010 or 2011, you might find two tech (or tech startup) events going on in a particular week. Now all three places have 2-3 events happening on any given night, and you can hardly choose which you want to go to, or if you want to spend the night just hacking and getting shit done (because that matters too!).
An example: In order to help run an event for Houston's Lean Startup Circle this past Thursday, I had to skip a talk at a startup speaker series and miss the launch party of Texas Medical Center's new Healthcare Accelerator.
Austin, has a better reputation (or just visibility?) on HN, but if you're comparing for places to live long-term, I wouldn't necessarily put it above Houston or Dallas in any absolute sense. My honest take is that tech in Austin feels more visible and "Valley-like" because of how small Austin is. Technology is simply larger in terms of percentage.
Single biggest resource is the Startup Houston blog/site [0], followed by the Houston Startups Facebook Group [1], and the Startup Digest calendar [2], both of which are linked to from Startup Houston. The calendar can be a bit cluttered, so working with the Lean Startup Circle [3], I help compile a monthly, semi-curated list of events that gets sent out to anyone who subscribes to "organizer announcements" within Meetup.
Plans are in the works for a unified calendar/feed for Houston's many, many Tech meetups, which currently have no central point of organization. Example of what I mean: there are 2 (or 3?) Python meetups, 3 separate UX meetups, and while there is a broader "Functional Programmers" meetup, the Clojure folks have their own separate one in addition.
Lastly, the three major coworking spaces inside the loop [4, 5, 6], as well as the SURGE seed accelerator [7] all put on good events. Not all of those events reliably make it onto the startup calendar, as each has its own little calendar page, but that's being worked on as well.
[0] http://startuphouston.com/
[1] https://www.facebook.com/groups/houstonstartups/
[2] https://www.startupdigest.com/digests/houston
[3] http://www.meetup.com/leanhouston/
[4] http://www.starthouston.com/
I ended up introducing hackathons and brown bag lunches to my former employer (a real estate brokerage).
Many of the really neat ideas I've had and pitched just don't go anywhere because either A) It's new and shiny, which corporate doesn't like (My company is in the Fortune 500 but we are painfully slow to market). or B) I'm expected to do things as they have always been done because "That's the way we do it."
sigh
There are also strong scenes in certain midsize markets that buck the larger trend (e.g. Austin, the North Carolina triangle, etc).
However, if you are in a midsize or small market outside of that handful of exceptions... then there are either few tech job opportunities at all, or the only jobs available are "line of business" type work that no passionate developer wants. It doesn't matter if you're in Memphis, Tennessee or Syracuse, New York. The problem isn't regional, it's market size.
Whenever I hear people griping about technology and "The Bible Belt", etc... I picture people fresh out of school who have never been anywhere and spend WAY too much time trading political memes on Reddit. Nonsense. There are plenty of technology hubs in large Southern cities, and plenty of backwoods hicks in the Pacific Northwest.