In addition to Mathematica, I should mention that the latest versions of Firebird (now FireFox) and Thunderbird are out from Mozilla.org. Winamp 5 is also out and its finally a release better than Winamp 2.x.
The new browser release is really an improvement. I never use IE anymore (unless there is some MS thing where they make you). With FireFox, Thunderbird, and OpenOffice, there is no reason to use any MS products on top of Windows. None. If I only understood the Linux file system better.