Currently the most recent version of Ubuntu Notebook Remix (Karmic Koala 9.10) available is the Alpha 5 release. It is a bit buggy but still worth the upgrade from Jaunty. One particular pain is that your touchpad won't be recognized properly and you won't be able to 'touch' to click. You'd be surprised at how often you use the feature when suddenly it's not there anymore. However the fix is pretty easy. All it takes is to install one piece of software from the Synaptic Package Manager.