I just read the graphic novel version of I Am Legend and never understood why he didn't think that an antidote could be made from his own blood. He was immune to the disease which meant he could fight it off, so why couldn't they create a cure from him?
I didn't like the way he went out, too melodramatic. It didn't have to be a happy ending, but he went out pretty lame for all the work he put into surviving.