Without a doubt Baird is the book that truly explains the application of the greeks to trading strategies. McMillan and Natenberg defined the parameters but not how to use them to really understand the behavior of a position or possible adjustments. It's only after reading Baird that I understood Cottle - which is very funny in parts. Cottle's book is difficult because it assumes you have the knowledge from McMillan, Natenberg, Baird, etc (afterall, it was originally targeted at MMs). All books are a must have. I also include Hull in my library as he mathematically defines relationships between the variables and these help me to pick up some subtleties (I may have to brush up on my calculus to produce the various relational graphs of interest).
The upside to this is that I am more confident in designing my positions and can readily analyses "complex" analyse. Mav is correct that you need to be able to trade the underlying to get the rewards. I'm still developing my system.
Thanks Mav and Riskarb for your contribution on the board. You guys have definitely raised the bar for a number of us.