FUS - Frequently Used Shortcut keys

What shortcut keys do you frequently use ?

Heres my list:
Ctrl+W
Alt+Space Bar+X
Win+D
Alt+F4
Win+R
Ctrl+Atl+Del
Ctrl+F
Shift+F3
Alt+Tab
Ctrl+Space Bar
Shift+Space Bar
Ctrl+B
Ctrl+Shift+ ->
Ctrl+Shift+ <-
Ctrl+A
Ctrl+Z
Ctrl+Alt+Z
F6
Ctrl+E

Winamp:
X
B
C
L

Gmail:
C
Ctrl+S
Space Bar
Tab

(more updates yet to come ...)