Before you answer this question, consider the reasons for making the investment in the first place. Are you interested in holding the property long-term for the appreciation potential or are you more concerned about cash flow? Answering this question will dictate the type of property you might consider.
There are various types of investment properties. Most novice investors start with a single-family or small multi-family unit such as triplexes and fourplexes. These are more manageable and generally affordable. Real estate investing, like most financial subjects, is something learned through experience. The more properties you've bought, renovated, managed and sold, the better equipped you'll be to profit from your investments. That doesn't mean you can't be wildly successful from the start; just don't expect to be.
If you buy a property in an upscale neighborhood, expect negative cash flow at least at the beginning of your investment. This is because rents in good neighborhoods generally don't rise as quickly as the price of the homes. If you need positive cash flow, better to buy properties in lower-rent neighborhoods. Some industry experts suggest buying investment properties where the monthly rent collected is one percent of the purchase price. Anything less and you won't cover your maintenance expenses.
Another strategy is the house flip. In this scenario, investors buy a house in need of repair, spend some cash renovating or bringing it back to life, then turn around and resell it (hopefully for a lot more money). Often, a house is simply run down cosmetically and a nice paint job will do the trick. Successful flippers should understand the difference between a house that is rough around the edges and one that is structurally unsound. A mistake of this nature will cost you thousands of dollars, not to mention a great deal of frustration.
Once you've gained the knowledge and capital to move into other areas, here are some interesting types of properties to consider:
Real estate can be an expensive hobby and you'll always need enough funds available for when things go wrong (they always do) and for repairs. Like in any business, undercapitalization can sink an investment property scheme fast.