The Pittsburgh MSA has got to be one of the top 5 most conservative. All of the counties in it sans Allegheny voted for Romney. A few of said counties, including Westmoreland County, PA; the most populous county other than Allegheny, gave him more than 60% of the vote.
I'd agree it's toward the conservative end but still a bit to the left of metros like Indy, MKE, or Cincinnati. In Cincinnati even the core county (Hamilton) is somewhat competitive (52.5% Obama) while the outlying suburban ones (Butler, Clermont, and Warren) are all over 60% Romney. Warren County is even pushing 70%.
Pittsburgh/Milwaukee is more debatable as MKE County itself is more Democratic than Allegheny, but the suburban three (Waukesha, Ozaukee, and Washington) are probably the most conservative suburban counties of any metro on this list.
Good points. There are also smaller metros that are very conservative. I'd still place Pittsburgh pretty high on the list, though.