The trend toward flat roofs is just silly in most areas (bc it causes water diversion problems, which then cause a myriad of other problems).

If you give more specifics on your situation in this thread, you might get more diverse input here.

Now for sure high tech was not as established as it is today and or as diverse.. there was no Google or facebook or linkdin etc. 

My only thoughts would be to make sure to buy in a stable/non-overheated market and make sure there are good diverse employment opportunities for your renters to secure your rental income, i.e. multiple strong industries.

The Kansas City metro area is so big and diverse, despite my growing up in the area, there are many places I've never been and I feel slightly overwhelmed by the glut of information I've been trying to absorb.

We are already self employed, but I want a new gig for diversity sake.  

Essentially the whole company pays when one segment of our business is hit hard because of the diverse global nature of my company.

This diversity helps by spreading my money around different 'baskets', creating various income streams, and increased my options in a downturn or any other major market event. 

Much more diverse economy.  

Personally, I like the diversity in my portfolio - I have all 3.