We consider a flexible greedy approach to wavelength assignment in an optical network with the goal of minimizing the cost incurred by wavelength conversions and fiber deployment. The greedy approach processes demands one by one in a certain order and makes a locally optimal choice for each demand. We address several heuristics for creating desirable demand orderings, including a random ordering, as well as a hybrid method that begins with a graph coloring algorithm. One of the primary strengths of our heuristics is that they are both simple and flexible. Hence, additional practical engineering and cost constraints can be easily incorporated into the approach. An empirical evaluation shows that our greedy approach works well on real-world networks under realistic demand loads.