MenuAndDockless is a SIMBL plugin for Snow Leopard and Lion enabling you to choose for every native Cocoa application wether it should show the Menu bar and the Dock or not. In addition you can save the default window size and position, automatically adjust window sizes or center windows and toggle a fullscreen mode individually for each application by customizable shortcut.

On smaller screens (on an 11” MacBook Air for example) this often makes much sense because you gain a lot of more free ‘space’ and it reduces possible distractions.

And because under Snow Leopard the Finder is also written in Cocoa MenuAndDockless even works for the Finder (just needs to be restarted once).

How to use it:
1. Download and install SIMBL
2. Download and install MenuAndDockless
3. Open (restart) desired application - e.g. myTumblr or Safari
4. Open its “Window Menu”
5. Apply individual settings for each application
6. Hit control+return (or custom shortcut) to show/hide Menu and Dock
> or use Menu: Window: Toggle Menu And Dock
7. Hit cmd+return or custom shortcut) to toggle the Fullscreen
> or use Menu: Window: Toggle Fullscreen
8. Use other actions to center, resize or position the active window

Requirements:
OS X 10.7+
SIMBL
Intel

Also available is:
Version for OS X 10.6