This is a good thread. While I already figured out the need for a helmet and lock, I never considered some of the other things. For example, I thought cycling clothes were really only meant for aerodynamics and therefore not really all that important. I probably should have guessed they'd have padding and pockets.
How much do you guys think you should spend on overall on accessories such as tools, lights and other essentials? As I ride more, I want to pick up all of these things but I'd like to know how much to budget.