Rob, What you should invest in is a personal preference. If you go to your financial adviser he will most defiantly tell you mutual funds because they can make money off of it. Advisors will almost never tell you real estate because there is no way for them to benefit. I would say buy a rental and use to cash to reinvest and buy more rentals so by the time you retire you will have a nice money making machine assembled. Real estate is multi dimensional asset class that makes you moneys in many different ways while you hold the property. It is also great for tax purposes. You have to understand though, its not completely passive. You will have many more head aches with real estate, but its all part of the experience. You need to ask your self if your ok with a more high maintenance investment. Even if you have a property manager, you will still have to manage your manager. In my opinion, its worth it.
As far as a market is concerned, the more boring the better. Cali and New York City are good examples of terrible places for buy and hold. Why would you buy a house for $1 Mil that rents for $3500 when you can deploy that same 1 mil and buy 10 houses for $100k each that rent for $1k per home. You can find a lot of good markets in the midwest. Indiana, Tennessee, Ohio, etc. The second biggest determining factor would be a great property manager. The property manager you pick will be everything when investing at a distance. They will make or break your investment.