You have several options when it comes to choosing the your top long-term investments. Your choice depends on several factors like exactly how much you can afford to invest, what type of returns you are looking for and how long is long-term for you. But the most important thing to keep in mind is that you should invest in markets with which you are familiar. For instance you should understand how to invest in real estate before you opt for this market and not just jump in because everybody is saying that it is a good opportunity. The same holds true for any other investments.Most people are attracted by the notion of a quick profit, but at least a part of your portfolio must include some long-term investments. You must be pragmatic about this. As your age increases, your income potential is likely to fall. Long-term investments will give you financial freedom after retirement. Whether it is medical expense or fulfilling a long cherished dream, you will be able to decide for yourself if you have made wise investments.There are some negative sides to even the best long-term investments. When you have made an investment, your money is also blocked for a long time and you will not be able to access it before your investment matures. Apart from this, long-term market trends cannot always be predicted correctly. If your investment performs poorly, you are liable to lose all your money.However, that is a common risk of every type of investment. Since we do not know what will be the condition of social security or Medicare in the future, it is safer to choose longer term investments.There are many different avenues of investments. These include stocks, bonds, real estate, funds and precious metals. It is difficult to decide which of these would be the best long-term investments.So, the golden rule of investment is that never invest in anything which you do not understand. Real estate is often a viable option, especially if you can locate a property with a lot of potential and can afford to buy it. You can remodel it and sell it for a profit. Renting can be quite lucrative depending upon the location of the property. It is recommended that real estate form at least a part of your long-term investment.Stocks are another option, but except for certain well established companies, they are not a good bet for longer term investments. Bonds are generally less risky. Most experts recommend that precious metals like gold form a part of your long-term investment because it is the best available store of value.Whichever option seems the best investment for you, you should follow a few ground rules. You need to be systematic about your investments. A good rule of thumb is to keep aside about 15% of your pay-check for investments each month. Finally, be careful when choosing your stockbroker or mortgage company so that your investment remains in safe hands.