Since Apple developed its "digital hub", with iLife and now iWork, I have wanted to have a system-wide panel that would let me choose pictures from my iPhoto library without having to open the application.
For example, if I want to add a picture to a TextEdit RTFD document, I had to launch iPhoto, chose the picture, and drag it to the document. Waiting for iPhoto to launch can be long if you have a lot of photos.
But there is a way to get around this, using an Automator action.
1. Open Automator, and click iPhoto.
2. From the list of actions, select Ask for Photos, and drag it to the right-hand pane.
3. Save this as a plug-in, and select Script Menu (the script menu that displays in the menu bar) so it is accessible anywhere. (If this menu is not visible, launch the AppleScript Utility in /Applications/Applescript, and check 'Show Script Menu in menu bar.')
Next time you need a picture from your iPhoto library, select this action from the AppleScript menu, and you'll have a media browser that lets you do so without opening iPhoto.
[kirkmc adds: You can do something similar if you need to select songs from iTunes. Select iTunes in Automator, then Ask for Songs. This lets you select songs from your library, from a specific playlist, or by searching in a Spotlight-type search field. You can also play songs from this window; you might not find this ideal to replace iTunes, but in a pinch, if you need to hear a single song, it will do the trick.]

