Freeware

Download CCleaner (slim)
Is this version a little slow on startup for anyone else?

Change log:
* Improved application startup time and INI loading speeds.
* Removed need to reboot for Index.dat cleaning.
* Improved cookie cleaning in Firefox 4.0 Beta 7.
* Improved Chromium based browser detection and cleaning.
* Added support for Adobe Reader 10 and Acronis True Image.
* Improved cleaning for 7-Zip, Adobe Reader 9.0, Microsoft Silverlight Isolated Storage, WinPatrol and Microsoft Management Console.
* Added support for local domains in “Cookies to Keep” list.
* Improved debugging with log file support using /DEBUG command-line parameter.
* Improved detection algorithm for 64-bit and Program Files.
* Improved folder drag and drop in Include options.
* Fixed bug in Uninstall Tool during cancellation.
* Improved drive detection in Drive Wiper screen.
* Added support to refresh cleaning rules using F5.
* Improved translations.
* Minor GUI improvements.

Microsoft/Sysinternals updates: Process Explorer v14.01, Autoruns v10.05 (source Sysinternals Blog)

Process Explorer v14.01: This update fixes a bug related to the DLL view and adds a tab to the new system information dialog, Summary, that displays all the performance graphs together.

Autoruns v10.05: This Autoruns update adds ActiveSync autostart locations, fixes a bug in that prevented offline scanning from working in some cases, and fixes a formatting bug in the scheduled tasks display.

This a a new version of CCleaner. Download CCleaner. According to the forums there is no longer a “slim” version.
*edit – apparently the forums were mistaken, The slim version showed up.

* A new 64-bit native EXE designed specifically for 64-bit systems.
* A new Drive Wiper tool screen under the Tools section, which allows users to securely erase the contents or free space on a specified drive.
* Improved support for Internet Explorer 9 and the Google Chrome browsers.
* We have also added improved cleaning support for HTML5 database storage, allowing CCleaner to effectively manage the next generation of web applications.
* Additional cleaning support for Microsoft Silverlight Isolated Storage.
* We’ve added three new environment variables (%SystemDirectory%, %SystemDirectory32%, and %SystemDirectory64%).
* New application icon.
* New Intelligent cookie keeping feature.
* and more…

Download or update from within the program (Help / Check for Updates).

Thunderbird 3.1.6 fixes the following issues in Thunderbird 3.1.5:
* Fixes a critical security issue that could potentially allow remote code execution. This issue does not affect email or newsgroups but could be triggered through browser-like features or add-ons.

Download or update from within the program (Help / Check for Updates).

What’s New in Firefox 3.6.12
Firefox 3.6.12 fixes a critical security issue that could potentially allow remote code execution.

*note – As of this writing Thunderbird 3.1.6 is currently being pushed to mirrors but is not out yet.

Download or update from within the program (Help / Check for Updates).

Thunderbird 3.1.5 fixes the following issues in Thunderbird 3.1.4:
* Several fixes to improve performance, stability and security, see the Security Advisory.
* Several fixes to improve the user interface and add-ons experience.

Download or update from within the program (Help / Check for Updates).

Firefox 3.6.11 fixes the following issues found in previous versions of Firefox 3.6:
* Fixed several security issues.
* Fixed several stability issues.

Driver Sweeper is an advanced driver remover / cleaner. See here for changelog and download.