The three largest costs for a data center outside of labor and IT equipment are: Real Estate, Power, and Bandwidth. So find a competitive power company (under $0.04/kwh), locate adjacent to a carrier hotel or major exchange (for cheap tail circuits), find an existing center buy it for $0.50 on the dollar and re-commission it.

If its a fallback or hot site it should be easy to get to by air and car,
should be on different utility grids, should be in different weather patterns, etc.

Avoid natural disasters:
Tornado
Hurricaine
Earthquake
Flooding
Landslides
WildFires
Etc.

Avoid potential manmade disasters such as:
Interstate and Rail Lines (Toxic Spills)

Find the best combination of the above, mitigate risk thru proper design and DO IT......

ATLANTA, GA

I'd love to be part of your team!