Then I thought: "the book is a classic of SF, and horror - surely this must be a case of Hollywood tinkering with a good story, improving it for focus groups and merchandising purposes". So I read the book.
It kicks arse, specifically vampire arse. If you've seen the film, read the book and think: "why the steaming fudge did they not just film this?". If you haven't seen the film, and don't want to, read the book. It is a classic, and rightly so. If you want to see the film, read the book afterwards. Not before. Otherwise you will sit there thinking: "oh fuckety-arse, they've shat all over the great story and now the title of the film makes no fucking sense".
In the book, Robert Neville smokes a pipe, grows a beard and uses paper plates instead of doing his washing up. Damn straight the last man on Earth is absolutely going to do those things. Will Smith didn't. I rest my case as to the relative merits of the two versions.