Book Promotion - What do you really need to do?

So I've been thinking a lot lately about things I need to do promotion wise for my new novel, and I was hoping to get some input from you all. I plan on posting excerpts in the near future and I'm also doing a book tour. But the one thing I'm not real sure if I need to do is a book trailer. I had never seen or heard of these before until I published my first novel, and I thought the idea for it was neat but I just wonder how effective they really are at promoting your work. What's your opinion? Do you like book trailers? Have you ever wanted to read a book just because of the trailer, or do you find the traditional way of reading the synopsis better? I'd love some feedback on this so please feel free to leave a comment or email me directly (see "contact me" page for email address). Thanks everyone and have a great Monday!