Like a lot of questions on this site, it depends on your financial situation, appetite for risk, among other factors. If you are risk averse and are looking to retire in the near term, investing in real estate, especially in this time period, is not advisable. If you have a greater appetite for risk and have a longer time horizon, I would definitely advise investing in real estate.

As per the question of what areas of the country, its hard to pinpoint specific parts. I would recommend looking at investment vehicles that investment in many different locales.

Buying to rent has plenty of logistical problems and requires a lot of man hours to just deal with these logistics. I would suggest sticking with more traditional investment vehicles for investing in real estate.