Gathering session cookies with Firesheep

One more thing: HTTPS makes front-end caching (aka HTTP acceleration) more difficult. You can't (or at least shouldn't) run a medium-to-high traffic site with dynamic content without a proper front-end cache.

For example, Varnish doesn't support HTTPS connections so you need to put something like Pound or Stunnel in front of it. OK so that's perhaps just a problem with Varnish (apparently Squid can do HTTPS reverse proxying), but still, that's making things more difficult for the webmaster/sysadmin in the current state of affairs.