Omnigraffle is pretty awesome for getting your ideas down for a client.  Here’s a bunch of templates and stencils I use almost every day to melt our clients faces at devnuts.

Konigi OmniGraffle UX Template

Konigi OmniGraffle Wireframe Stencils

iPhone/iPad Apps

ExtJS 3.0 I use this for basic panels to be coded with Sencha.

UI/UX Resources

• Assorted UML Stencils From Graffletopia
• Wireframes Magazine
• Patternry - UI Patterns
• UX Magazine
• Boxes and Arrows