I believe Harris county was 50/50 Obama/Romney. That is amazing for a major metropolitan area.
But be forwarned. In ten short years I saw Fairfax County go from 60/40 Republican over Dem to 60/40 Dem over Republican. The only thing that changed was the population increased, and the increase was primarily drawn from urban cores (and south of the border, a problem of which folks in Texas are certainly well-aware).