We used to hear complaints about the default settings in Photoshop’s various layer effects, especially about strokes always starting out red. In CS4 we changed the stroke default to black, but that was just a stopgap measure that didn’t address the fundamental problem: No matter what we might pick, people want effects to start with whatever values they happen to prefer.
For CS5 we thought about making layer styles sticky. That is, after you applied an effect with a particular set of values (e.g. Drop Shadow at 50% opacity), the next time you applied that effect, the dialog would start out using the last-used values. Sometimes that behavior works well, but just as often it can be confusing and annoying.
We therefore opted to add a pair of buttons (see screenshot) to each effect–one to establish the default values you prefer (“Make Default”), and one to restore the “factory settings” for the effect (“Reset to Default”). The wording of the latter isn’t quite as clear as I’d like, but hopefully it’ll make sense to people.