Analytics firm Altos Research named Las Vegas, Chicago and Pittsburgh as the top-three cities real estate investors should target – but for different reasons. For Vegas, it's obvious. Prices there were cut in half from their peak in 2007 to a median home price of $137,930 and a median rental rate of $983, according to Altos. The resilient and diverse economies in Chicago and Pittsburgh boosted those cities' attractiveness. Even though median home prices are still high -- $279,385 in Chicago and $157,544 in Pittsburgh – the rental numbers work and there is plenty of demand, Altos said. An honorable mention went to Detroit. Very low prices, sometimes three- and four-figures, provide a very clear bottom for investors to get in as employment improves. "There are some big hurdles to overcome," analysts said. For the month of October, Altos reported prices shrank in 13 of the 20 markets on its composite index. The median prices dropped 0.43% to $254,407 in October from $255,309 the month before. Sellers are working through the inventory, pushing it down in each of the 20 Altos markets. The most savvy investors, Altos said, are not looking at distant price appreciation as the main gauge for their return but low enough deals to produce a solid cash flow from rentals. "Could prices drop further? Sure. In fact, the real-time trends indicate it’s very likely prices will drop further. But will prices plummet from their current levels? Doubtful," Altos said. "The biggest hit to real estate prices has already happened. The lack of volatility in prices over a five-month period is evidence of near-future price stability." Write to Jon Prior. Follow him on Twitter @jonaprior.