This is one of the best Windows utility I have seen. Which is very handy.
QTTabBar - It allows you to add tabs in your Windows explorer.
Preview text and image files in tool tip
Customizable Tab width,height tab color
Customize Explorer background.
Option to undo close window.
List of closed windows etc
Just see some screen shots
Too many options you have, and no more cluttered windows on task bar.
Download Qttabbar, and enjoy.
Activate QT Tab Bar, Qt Standard Tab Buttons on Explorer
Enable QT Tab Desktop Tool from task bar.
Also you key board shortcuts
Ctrl + Tab: select next tab
Ctrl + Shift + Tab: select previous tab
Ctrl + Num0 - Num9: select a tab directly
Ctrl + W: close current tab
Ctrl + Shift + W: close all but current and locked
Ctrl + Shift + Z: restore a tab
Ctrl + O: open dialog for folder
Ctrl + L: lock/unlock current tab
Ctrl + Shift + L: lock/unlock all tabs
Ctrl + N: clone current tab
Alt + Left/Right: go back/forward
Alt + Ctrl + Left/Right: go back to the start/forward to the end
Alt + F4: close window
Alt + ,: show application menu
Alt + .: show current tab menu
Alt + M: show/hide menu bar (Vista only)
I could not find any big change in the use of memory also, but I haven't done a study on this. So check it out. Am sure you will love this.