UI Enhancements

AveDesk is a tool that enables desklets on your desktop: desklets are small graphically pleasing mini-applications that are useful and fun to use. A desklet can be anything, a small sticky note, a weather foresight, a calculator, etc.
LClock is a Win32(64bit too now) Longhorn systray clock program.
MacSound a sound volume control in Mac OS X Style.
RocketDock is a smoothly animated, alpha blended application launcher. It provides a nice clean interface to drop shortcuts on for easy access and organization. With each item completely customizable there is no end to what you can add and launch from the dock.
Taskbar Shuffle - rearranges the programs on the taskbar by dragging.
Y’z Dock is a program launcher like the dock in MacOS X.
Y’z Shadow adds a shadow effect to the windows in pursuit of the "beauty of a shadow". It makes it possible to select one type of shadow effect in the active window and a different one in the inactive window. The user can also choose to have transparent menus. There is also the option of selecting the degree of transparency in the menus.
Y’z Toolbar - change the toolbar icons in Explorer and Internet Explorer
Visual Task Tips - thumbnail preview image for each task in the taskbar.
Icons and Folders
Badges the program that allows placing handy emblems upon familiar Windows icons.
Folderico allows to change icons of the chosen folder to any chosen by you. And even at connection of a hard disk to other computer of an icon will remain such what they were made by you.
Folder Markeris a tool to mark your folders.
Folder2MyPC - add favourite locations to My Computer.
Microsoft TweakUI - system settings.
Vize - Basic is a GUI enhancer for Windows Vista. It replaces most of the non-Vista icons, animations and bitmaps that Microsoft is still overlooking.
IcoFX is a free icon editor that supports Windows Vista icons also. It can extract icons from exe and dll files. Can convert images to icons. It can do also batch processing.

Shell Packs
BricoPacks - shell packs that make your XP look like Vista while staying fully compatible with Windows XP.
ShellPacks shell packs that change your Windows XP look.
Tango Shell Patcher is a graphical wizard designed to make simple the process of modifying your system files with resources developed and inspired by the Tango Desktop Project.
Vista Transformation Pack brings to your desktop the look of Microsoft's future operating system, Windows Vista.
With Vista Sound Scheme you cann upgrade your old sound scheme with the new Windows Vista sounds Karachi Exporters