If you rely solely on appreciation, you are no different than a stock market speculator. If you buy properties in distress - foreclosure, divorce, etc, you can always find a deal in any market.
Here’s a question that I hope will stir up a insightful and useful discussion for us all:
Which markets in the US are the hottest for real estate investing?
Feel free to qualify your answer by the type of real estate (multi-family, single-family, mobile, commercial) and/or type of transaction (flipping, lease option, notes) for which you think your recommended location would be good, as well. I believe a discussion at the county/metro level would be most useful, but feel free to make your answers as specific or general as you like.