It's impossible to know what you'll need in the future. No one should be wasting too much time trying to figure it out.

How could Zuckerberg -- or anyone, for that matter -- have predicted the kind of rampant success Facebook has had? Who thought in 2005 that Facebook would become the largest photo sharing site on the web? Or that they would need to handle almost 140 million unique visitors per month?

If the largest problem of your business is your application stack, you are in a very good place. Most businesses have much larger problems like, say, cashflow.