On Fedora 16 running Gnome 3 by default if you press ALT+Print Screen or simply Print Screen you get this window:

Sometimes I find this really annoying because it adds a step that I don't want. I would rather not see the gnome-screenshot window and simply have the image in the clipboard ready to paste straight into GIMP.
Default gnome-screenshot configuration

[me@mybox ~]$ gconftool-2 -g /apps/metacity/keybinding_commands/command_screenshot
gnome-screenshot
[me@mybox ~]$ gconftool-2 -g /apps/metacity/keybinding_commands/command_window_screenshot
gnome-screenshot --window

gnome-screenshot configured to send the screenshot straight to the clipboard

[me@mybox ~]$ gconftool-2 -s /apps/metacity/keybinding_commands/command_window_screenshot --type=string "gnome-screenshot --window --clipboard"
[me@mybox ~]$ gconftool-2 -s /apps/metacity/keybinding_commands/command_screenshot --type=string "gnome-screenshot --clipboard"

List Settings after them being changed to clipboard mode

gconftool-2  /apps/metacity/keybinding_commands -a command_2 = 
command_window_screenshot = gnome-screenshot --window --clipboard
command_1 = 
command_screenshot = gnome-screenshot --clipboard
command_3 = 
...

Set them back to their defaults

[me@mybox ~]$ gconftool-2 -s /apps/metacity/keybinding_commands/command_window_screenshot --type=string "gnome-screenshot --window"
[me@mybox ~]$ gconftool-2 -s /apps/metacity/keybinding_commands/command_screenshot --type=string "gnome-screenshot"