Everything I have read in the past indicates that Bounce rate is not used by Google to calculate where you show up in search results. However, I have also read some articles where people have indicated that websites with high bounce rates where affected by the latest Panda update.
Google really doesnt share the specifics regarding their algorithms. Regardless, it is good, everyone would agree, to focus on lowering the bounce rate. If you have a high bounce rate, you need to determine what you can do to keep your visitors from leaving your site when they arrive on that landing page.