I've been touting the greater Cleveland market as the best rental market based on the relationship between rental income generated and the cost of the property that is going to generate it. This goes to ROI directly and not to appreciation at all.
I have read a couple of articles from Fortune and The WSJ that reported on a Moody's Analytics study from last year (haven't seen one for 2012). The articles are generally geared toward whether "now is a good time to buy" or not. The price-to-rent ratio is an indicator of whether buying or renting is the better choice, but it is also kind of like a P/E ratio for investors.
Here's what the WSJ said...
"Of the 74 housing markets, Baltimore appeared to be the most overvalued. By contrast, prices in Cleveland, the most undervalued market, have returned to 1991 levels based on the price-to-rent ratio."
(full text available at http://online.wsj.com/article/SB10001424052748703313304576132291585938656.html)
[For a better explanation of price-to-rent ratio, see http://online.wsj.com/article/SB70001424052970203914304576630891758741406.html (starting at the 4th paragraph).]