Or you can use cmd+shift+4 instead of cmd+shift+3. This allows you to select a region on the screen or you can press
spacebar, mouse over the window you want to copy and press enter.
As far as I know you're right. Depending on what you're doing, Automator or the command line screencapture tool combined with a shell script or QuickSilver might be worth looking at to speed up your workflow.
You can also hit 'space' after cmd+shift+4 to get a little camera icon that takes a screenshot of only the window you click on. It works for any window, the desktop, the menu bar, any menu, and interestingly enough: all of the icons sitting on your desktop independent of anything else.
