Windows 7 is really fast, but I crave instantaneous performance. Here's my favorite UI tweaks so far. These tweaks speed up the Desktop Preview, Thumbnail Preview, and the Window Preview. I have mine all set to 0 milliseconds but the range can be set between 0 and 100+, experiment with your own system to see what settings you like best.
First there are some keys that need to be added or modified (I had to add them on my system) in the registry.
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced]
"DesktopLivePreviewHoverTime"=dword:00000000
"ThumbnailLivePreviewHoverTime"=dword:00000000
"ExtendedUIHoverTime"=dword:00000000
Now to really see the enhancements that these tweaks provide there is some settings to change in Performance Options.
(http://soap75.home.mchsi.com/Performance_Options.jpg)
Uncheck the following:
Animate controls and elements inside windows
Animate windows when minimizing and maximizing
Animations in the taskbar and Start Menu
Fade or slide menus into view
Fade or slide ToolTips into view
Fade out menu items after clicking
After your done log out, or restart for the settings to take effect.