Unassociate File Extention Type

See also:
An Utility to Unassociate File Types in Windows 7 and Vista
How to Unassociate, Remove or Delete Programs From “Open With” or “Recommended Programs” List

Create an XP Mode for Windows 7 Home Versions & Vista

(from Lifehacker.com)

Windows Vista with a Live Thumbnail Sidebar

Five Free & Phenomenal Vista Utilities

• Launchy: a simple and easy to use start-up/launching application;
  
• TweakVI Basic: an automated window resizer;
  
• Sizer: allows you to tweak settings both available and hidden throughout Windows Vista's GUI;
  
• Vispa: similar to Sizer, but with much more options and versatility;
  
• AllSnap: an applet that provides a big convenience in how your desktop windows sit next to each other and the edges of the screen.
  

Fix Disappearing System Tray Icons in Vista

PreviewConfig Adds File Types to Vista's Preview Pane

Turn Off Vista's Auto-Tuning to Prevent Browser Slow-Down

Supercharge Windows Vista's Startup Time

What happens during Vista's startup and how to improve boot times.

Get Rid of the Junk Left Over after You Install Vista SP1

Speed Up Windows Vista

Useful Windows Vista Sidebar gadgets

See also:
7 gadgets for your Windows Sidebar

A Cost Analysis of Windows Vista Content Protection

"This document analyses the cost involved in Vista's content protection, and the collateral damage that this incurs throughout the computer industry."

More performance updates, fixes for Vista released in advance of SP1

Four Must-Have Vista Updates

(from ExtremeTech.com)

Windows Vista Tips, Tweaks & Sidebar Gadgets

As the subject says.

(from LifeHacker.com)