Seth Godin shares some useful insights on why bullets don't work in presentation in his post Most presentations aren't bullet proof. He says bullets don't save time and don't make easier to remember things.
Don't miss navigating to the link to his bulletless solution in his earlier post.
I find it so hard to resist using bullets in my presentations, though I must admit the most remembered presentation I made didn't have bullets. There must be some truth to what he says. Interestingly when I blogged about that presentation, I was inspired by Seth at that time too.