For years I have been trying to explain to people what the crawlers actually see when they come to your website.  The best estimate was always a Lynx browser.  I always had a hell of a time trying to get Lynx to run until finally I found a Firefox addon, Yellow Pipe Lynx Viewer.  However, I still had issues with redirect, secure pages and pretty much anything else you could think of.  Playing around in the Google Webmaster Tools today, I came across an option to Fetch as Googlebot.  It doesn't give you something crazy or unexpected, just a simple fetch of your page.  However, it is certainly nice to know, instead of guessing, exactly what Google is fetching from your site.