Great list. One I would add would be understanding what the client's problem and building an appropriate solution. Too many times I've seen developers just dive in coding up the solution the client suggested without trying to understand the problem the client is trying to solve. For example, by adapting the problem to using an existing CMS or SAAS you can avoid a huge amount of custom coding.

A good developer would be able to write simple code for a given solution but a better developer would suggest a simpler solution leading to even simpler code.