usability
Where am I, where did I come from, where can I go to? That's web usability in a nutshell.
My philosophy: Keep It Simple. This is important to visitors as well as to site editors.
How? By using clear language, the right design, and a clear structure.
maintainability
In my opinion a website should be easy to maintain, without any technical knowledge. If not I haven't done my job well enough.
quality
Whatever I do for you, as a customer you should not be dependent on me. That's why I choose Open Source software. That's why I properly document all my stuff. So you'll choose me based on quality.