The fact that you cannot drag files to their icons and have that file opened in the application seems like something out of the past.
To scroll a window in Windows, the window needs to have focus. To scroll a scroll pane in an active window, that pane needs to have focus -- it is maddening especially when hover events work for non-focused windows and panes.
I could go on and on, but this isn't a Windows hatefest.
Command + c will copy the highlighted spotlight result.
Expose (show all windows) and drag and drop files to that window (i grab the file, while dragging show all windows by either a keybord key or hot corner and drop it to the new window)
Hold down command to move around background windows without giving it focus.
Ctrl + (arrows or numbers) to go to certain spaces.
While in spaces expose, hold down ctrl to move all of the windows of a certain application to another space.
Hold down a window's titlebar while switching spaces to move that window to the new space.
Drag folders that you frequent into the left side of finder. I have /private/etc in mine
Hold down command while clicking or pressing enter on a spotlight result will open its containing folder.
How did I forget about keyboard modifiers by holding down the alt key.
Drag a file/folder to terminal to get the path to that file printed in terminal. so I often type "cd " and then drag folder to get there
While switching apps via command+tab you can let tab go and either hide the application by pressing h or quit it by pressing q (I wish that you could minimize it by pressing m). You can also cycle backwards by pressing tilde (this only works if youre already command+tabbing) or shift+tab
* Gone from snow leopard, but i miss it* there used to be a keyboard shortcut (command, option, ctrl space) that opened a list of your last accessed files (i mistakenly found a bunch of porn website cookies on an intern's laptop once). This used to be useful to see which files you needed to upload /ftp.
In a single universal field you have instant: app launcher, calculator, dictionary, file search, email search, contact search.
My single best tip for Mac power-users: learn what you can do with Spotlight.
Edit: grammar
kind:pdf
date:yesterday
author:short_name
from:contact_name
And the boolean relations AND, OR, NOT work as you might expect.
There's a lot of cool stuff hidden in Spotlight. Try
man mdfind
Thankfully, you can do this now in 10.6 - drag the file to an already open application and hold it there for a few seconds. Then the app comes up, then (without ever releasing the mouse button) drag the file to the application window, and hold for a few seconds. Now you can drop your file in that window. The whole process takes about 5-6 seconds (which is agonizingly slow), and, IMO one of the worst aspects of application-driven window management (versus window-driven window management).
Just add desktop as a toolbar on the task bar, uncheck all the text and make it take full line, so as not to conflict with running apps. Then drag files onto those icons and they will be opened in new or running instances, whatever apps are designed to do.
Edit: so it looks like this: http://dl.dropbox.com/u/15669592/taskbar.png
Katmouse http://ehiti.de/katmouse/