There’s value in presenting a crude first cut of a design. It keeps the customer focused on the essence of the problem, and not the incidentals (“hey! I think I might want a blue dropshadow!”).
I might be late on this, but Balsamiq Mockups is the perfect tool for making rough comps for a user interface.
I haven’t pulled the trigger on the pay version yet, but just playing with it is fun. If your freehand art is too crappy to show to others, and you don’t want to present a perfectly polished page for initial reviews, this is a nice tool to have in your utility belt.