Frank, I have to agree with the hourly rate idea. Its the only way to have a real basis for justifying costs for a project. Otherwise you end up over time magically creating fees for projects that can vary widely. Not a great way to build trust in the market place.
I would start with a honest appraisal of the amount of hours you think it will take to complete the project. Then add a few hours to cover changes and reviews. For rates, I have seen them all over the board, but for most professionals they seem to be in the $100 to $200 range. Where you sit in that range really depends on how talented you are and how busy you are. Its a bit hard to charge $200+ an hour when you only have one client.
David Richter
Richter Studios
http://www.richterstudios.com
Chicago’s Video Production, Interactive and Presentation Services Company