I've tweaked the layout a bit so that you can scroll the posts while keeping the sidebars and header in place.  My goal is to ultimately make it so that all the sidebar content fits onto a typical screen so that you can see all the archives, search, etc without having the scroll the page, and you only have to scroll the post content.  Let me know if this is good/bad for you.  I'm probably going to keep playing around with this for a few more iterations, so please excuse me in advance if you stop by and things are little out of whack.