An alternative would be to click the "Show View as a fast view" icon in the lower left hand corner of the Eclipse window and choose "Help".  When the Help view pops up, make sure "Related Topics" is selected.  To hide a fast view, simply click anywhere outside of it.  Now, if you click on or select a class, property or method and then click the Help fast view - it will display a list of help topics that are related to your selection.  This approach may not be as quick or graceful as Shift+F2, but the advantage is that it offers links to related articles in addition to the regular as docs.

See it in action:

Please keep in mind that these techniques will only give you the official Adobe documentation.  Your docs, and 3rd party library docs will not show up in the help view.

If anyone has any other fancy tricks, let us know in the comments.

Shortcuts:

1. Go to Definition:  Ctrl+Click on function name or variable to go to it's definition.
2. Auto Complete:  Ctrl+Space will bring up that handy list of auto-completion options.
3. Ctrl+/:  Comments or uncomments the selected line(s).
4. Ctrl+Shift+C:  Adds or removes block comment to selection.
5. Quick Outline:  Press Ctrl+O when editing an .as or .mxml file to get a list of class variables and functions.  You can type a few characters to filter the list, and when you select one, the editor will jump to the definition.  This is way faster than using the outline window or Ctrl+F to search for something.
6. Ctrl+Shift+T:  Browse all class types, select one to view the class definition.
7. Alt+Down & Alt+Up:  Moves the selected line(s) up or down.  This is great for re-ordering variable declarations, mxml attributes, etc.
8. Ctrl+Alt+Down & Ctrl+Alt+Up:  Copies the selected line(s) and pastes them above or below.  Combines 3 steps (select, copy, paste) into one!
9. Alt+Left & Alt+Right:  Work like your browser's back and forward buttons for your navigation history.  This is especially useful when you are control-clicking or "quick-outlining" to function or variable definitions.

Other Savory Tips:

1. To create a series of nested folders in the project navigator, open the new->folder dialog and enter a path (e.g. com/rphelan/controls).  Eclipse will automatically create all folders in the path if they don't already exist.  This is very useful when first creating a project.
2. You can double-click to maximize/restore any panel in Eclipse.  I frequently expand my editor window to show the maximum amount of code possible.  (Note:  this does not legitimize writing super long lines of code.  I recommend wrapping at around 80 characters)

If several of these are new to you, try out just one or two at a time and see how you like them. Once they are second nature, try adding a few more. My theory is that the less I have to rely on my mouse when developing the better.

Want to learn more? Don't forget that you can bring up a list of relevant shortcut key options at any time by pressing Ctrl+Shift+L.

Note: Mac users - just swap out the command key for control in each of these combos.