I recently made a blog post about how to upgrade Drupal's jQuery version from 1.4.4 to 1.8. The problem is, popular contrib modules (views being the main culprit here) and even some core jQuery require an outdated version of jQuery (be 1.4.4, to be exact.). There is a module called jQuery Update, and it works well, but if you need a self contained theme (with no module dependancies) this might be helpful to you.