On Monday, Google rolled out an entirely new Google Reader, and today it previewed a big list of changes coming to Gmail. While we saw some of these in a leaked video in October, the the Gmail blog's official post this morning reveals dynamic window resizing, a new button for tweaking display density, several new high definition themes, and profile pictures. Email threads have been tweaked into a more conversational view, reminiscent of Wave, that makes messages look similar to a chat window. The classic search options are still there, but they've been enhanced with new search fields to narrow down by from, to, subject, and more. And, finally, you can create new filters from the search box, saving you the need to jump into a message or the settings tab. In the coming days, Google will add a new button in the bottom right of the site to let you toggle on the new look.