OK newbs, here's some stuff from OS 7.5.
To access the folder structure back to the root (Mac HD) command click on the title bar of a finder window.
in a finder window start typing the name of a file to select it.
or use the arrow keys to select an item in the finder. To open hid Command down. To go back a level hit command up, to do either of these and close the window behind hold the option key. Keeps your fingers on the arrow keys for super fast file navigation.
In list view in a finder window, hit command right to reveal folder contents, command left to close. Command option right reveals all folder contents. This works in dialogue boxes too.
(it used to be in System 7.5 Cmd right and left to cycle disks, and Cmd up and down to open/close)
Command option W closes all finder windows.
Make clippings, rather than copy/paste to the clipboard. Drag a selection onto the desktop and keep it there.
Some cool ones that appeared in OS8
When you drag something onto a folder/disc, hit space to open the folder's window up. Spring loaded baby. It don't work too good in X these days, too much weird tab bar stuff.
Right click! On everything!
Some OSX only useful finder tweaks
Command Shift A selects applications tab
You can also drag icons to the title bar! Put a regularly used navigation item like Adobe Bridge, Firefox or iPhoto next to the forward/back buttons. Then it's conceptually just another form of window. Object Oriented stuff is amazing isn't it.
Say you have a folder open and you want to copy it. Just click and hold on the folder icon on the title bar, it should pull off. You can then put it where you like.
To get rid of the weird windows style tab bar stuff on the side of the Finder window, hit Command option Tab. If you don't have a huge display this means you can see more stuff. Also, like an older finder window, it keeps all the windows you've seen open, rather than having a back button. To stop the screen from filling with finder windows, hold down the option key when opening : option doubleclick, cmd optionO, Cmd option down etc.
You can stick folders on the dock provided that you put them to the right hand side of the line. Right click to get a menu. It's just like the old apple menu. Except more of them. And upside down. Stick your hard disc in it and browse it in submenus. Or your documents folder.
[size=4]Some Essential Photoshop tweaks that nobody knows but everybody should:
Switch off all palettes : TAB
Switch to fullscreen/fullscreen no menus : F
This goes for Illustrator too.
A little known QuarkXpress feature: hold command option shift delete with an object selected. An alien wanders on screen, and zaps your item with a raygun, and it disappears in a tacky orange gradient effect. I'm serious. It works in 3.3. I dunno if it's still there, i've defected to InDesign.