You have to have the right people skills, the right management culture and the right behaviors. That's much more important than picking exactly the right tool, or making sure you have your data model exactly spot-on right. You learn that value will come from being prepared for the unexpected. Long before we had any business intelligence stuff, in response to a fuel crisis, we had to analyze in a very short time frame fuel costs, fuel usage and so forth - it was costing the airline a small fortune. With a good business intelligence strategy, you're not caught short by the dynamic, changing airline environment.
Data grows like a weed.
You never stop needing more hardware. I've got as much disk storage on my PC at home now as I had on our first data warehouse. Your return on investment is zero unless you start making some decisions off the information. Don't change your mind too often regarding business intelligence tools. No one tool can be the feature-leader across the board all the time.