Another Designer, I am in a similar situation with a client, I have just been using wordpress for over a week now and LOVING IT. OMG, they did me such a favor, I am going to move all my sites to it! Just remember, when you first install it, uncheck the box that says something like search engines will pick it up. You don't want that while you are working on the site, just remember to reactivate it when done. Also, as a newbie, I am finding the wordpress codex the best helper! Also, this thread, just posted last week helped me A LOT!
My question to people here is this...What can't be done with wordpress? As a newbie, I am still worried that something will popup that I can't use wordpress for.
Good luck, new doors and new streams of income/opportunity are coming your way.