Currently when I leave my desk I lock my screen and that turns off the monitor and then when I return and move the mouse I need to enter my password.
The problem is I never get to see my screensaver when I return.
How do I have the security of locking the screen but instead of turning off the monitor is should immediately go into screensaver mode. Then when I move the mouse it must exit screensaver and request password.
Similar to Windows XP
22 Answers
If you have your scrensaver settings configured to lock the machine when the screensaver activates, simply manually activating your screensaver (e.g., by a hot corner) should leave your desktop "locked" in that deactivating the screensaver should request a password.
You can configure your screensaver to require a password to unlock again in System Preferences » Security:
In System Preferences » Desktop & Screen Saver » Screen Saver you can configure your screen saver, after how long it should appear, and even Hot Corners of your screen, where moving the mouse there would activate your screen saver.
Another way to start your screen saver is to execute the following application:
/System/Library/Frameworks/This application starts the screen saver. Put it in your Dock, your Finder's sidebar or toolbar, start with your preferred application launcher, Automator Service, AppleScript or whatever you want.