OmniGraffle Pro rocks for wireframing - I use it all the time. Be sure to add some web-specific stuff to your Stencil library - I use the ones here, and judgin

OmniGraffle Pro rocks for wireframing - I use it all the time. Be sure to add some web-specific stuff to your Stencil library - I use the ones here, and judging from the labels in the mockups in the video, so does that guy: http://konigi.com/tools/omnigraffle-wireframe-stencils http://konigi.com/tools/omnigraffle-wireframe-stencils In addition, learn how to effectively use grouping and layers, especially shared layers - this is functionality that's easily missed if you just open OmniGraffle and start screwing around with it, but it's so useful. Should you have a subscription, lynda.com added a decent OmniGraffle tutorial not so long ago.