If you've noticed I've been referring you to Smashing Magazine quite a bit, it's only because they have fantastic content I'm usually dying to share with you. This time it's their Top 10 Killer Photoshop Combo Moves.
For example... Killer Move #10 is what they call the "Cloak of Invisibility" which removes everything from your screen except your file. That definitely comes in handy when you quickly want to see only your stunning creation without the distraction of palettes (now called panels in CS4).
There are 9 more just as useful tips offered by author Tom Giannattasio.