In a word : Now!

Property is not a phenomenon of the last few years; it has been a secure investment for quite a considerable period. It will remain so as demand continues to rise. 

Building wealth is about getting compound growth and to get compound growth you need to stay within one market sector for at least a full cycle. Some advisers suggest a minimum of seven to ten years. Others suggest a range of 10 to 20 years to gain the maximum advantage of the long term cycle. All agree that property is not a get rich quick investment. It repays patience, and it rewards good preparation and careful management.

There are opportunities in every market. If you buy in a growing market you may pay a bit more for your property but growth will soon help you along. If you buy in a depressed market, you can ususally find better priced properties and you are ready to benefit when the market turns positive again. 
 

Remember the adage, "it's never a bad time to make a good investment".