G App Launcher for Chrome and Firefox gives you the option to create a menu that stores all your Google service shortcuts (up to 1000), allowing fast access to those that are used frequently.
You can choose from over 1000 different Google shortcuts that can be changed to buttons within a space-saving popup. The popup is displayed adjacent to your address bar and can include Gmail, Google Reader, Google Maps, Google Calendar, and many more in just two clicks from your browser.
Shortcuts for Google has one nice organizational feature; it includes the ability to sort and arrange the buttons to suit your work/browsing habits. You can also customize which shortcuts are displayed in the drawer app and add custom entries.