Before one knows where they should investment they have to understand what they own and why they own it. Step 1.
Step 2. Determine what your comfort zone is with respect to volitality, the time line you're going to need access to these funds
(ie a downpayment on a home has a different time line than do retirement funds)
Step 3. You may wish to determine how much you need. For example if it's for your retirement do you have a pension (indexed?) CPP, OAS, rental Property, business interests. etc)
These will all come into play, along with the amount you have available to invest on a regular basis. This should allow you to determine what rate of return you require
to meet your objectives. Some may need 10% some may need only 5%. If it's the latter one could invest in fairly safe investments and achieve their desired results, which
is a comfortable retirement. If one needs 10%, you'll either have to fall within this risk tolerance profile. (ie be comfortable with a heavy exposure to the stock market) or
be prepared to contribute more, or work longer.
Step 4 Construct a portfolio that reflects the outcome of this analysis. and if one simply wants only one suggestion and ignores all this, corporate bonds
within the context of a balanced portfolio would be my suggestion.
I'm personally not a big fan of the buy stock x and hope you hit a home run approach. That's more along the lines of gambling rather than investing.