Matt, What would you suggest I do in this case:

I graduated in May 2009 and have been working in the industry for 2 years. I worked with a professor for my senior project. I recently emailed said professor asking for a letter of recommendation, and I received no response. It's very hard for me to know whether he ignored the email because he was not enthusiastic about writing the letter, or because he forgot / did not receive it / whatever. What do you think is the best course of action here? Wait for a week and then send another email? What if he doesn't reply again?