Leopard's Stacks feature
One of the first Leopard features I started using was Stacks. I used it to replace the program launcher I'd been using. The Dock is a great way to organize your most frequently used apps but since it also gets populated with an icon for every program currently running on your Mac, it can get a bit cluttered. Fortunately Stacks offers a great way to tame that unruly list of icons.
Leopard comes with two Stacks items by default, Documents and Downloads. I've gotten rid of Documents since I tend to keep my documents stored in a hierarchical directory structure rather than shoving them all in one big documents folder. I've also made a minor change to the Downloads item. Stacks has the annoying habit of changing the icon for the Downloads or any other Stacks item in the dock to icon of the first item in that folder. I find that disconcerting to have my Downloads folder sometimes look like a folder and sometimes look like the icon of whatever program I've happened to download. So I've added an alias for a folder called _0_dummy_folder to the Downloads folder (in your home directory). The name causes the folder to appear first in normal sort order so a folder icon is used for the Downloads Stacks item.
I've also added a few new Stacks items of my own to the Dock. I did this by following the procedure below:
1) Create a folder to contain the entries you'd like to appear in your new Stacks items. For example, I created a folder called ~/Dock/Utilities to hold aliases for all my frequently used utility programs. Note that the tilde is Unix shorthand for your home directory.
2) Create and drag aliases for each utility program you want appearing in this new Stacks item to the folder you created in the previous step.
3) Create and drag an aliases for a dummy folder to the ~/Dock/Utilities folder. I use an alias to a folder called _0_dummy_folder for reasons outlined above.
4) Drag the folder ~/Docks/Utilities to your actual Dock. I dragged mine to the left of the Downloads Stacks item.
You can repeat the above procedure to create more categories of frequently used programs or frequently accessed documents. The best part is I don't have to keep paying to update my program launcher. This also takes up less space than my old program launcher.