1) Ubuntu Tweak
Ubuntu Tweak allows changing all the itsy-bitsy pieces of Ubuntu desktop OS. It is the equivalent of TweakUI for Windows. You can achieve the same results by using the gconf-editor tool in Ubuntu. Ubuntu Tweak also helps install third-party upgrades in a simpler fashion so it definitely gives a new boost to your clumsy Ubuntu desktop and increases UserExperience.
I am with love with Google Chrome! It is the simplest browser I have ever used! And looks great on Windows Vista.
Can't find any bugs yet but the first release of Google Chrome Beta (Build 1583) does not pass the Acid3 test; it scores 77/100 and does not render the image correctly, nor does it correctly render the ACID 2 test when the browser window is resized post rendering; as a result it fails to fully adhere with existing webstandards. Other standards compliant browsers like Firefox 3.0.x do not have this issue.
Let's have a quick look on its features (source: Wikipedia):