If you have made the switch to Google Chrome, as I did long time ago, then this tips are is going to save you some time:
Did you close by mistake a tab?
Click Command+Shift +T and there you have it again. (Control+Shift+T for Windows)
Going to the search bar?
Click Command+L and the cursor moves to the search bar selecting everything so you can just start typing
Synchronising Extensions, bookmark on all your computers using Chrome?
Go to Preferences, Personal Stuff and log in with your Google apps or Gmail account. You can sync bookmarks, extensions, forms, etc… across all your computers using Chrome. Neat.
You normally search using Google, but if you often search in other search engines, such as wikipedia, amazon, bing, etc… you can create easy shortcuts without having to go to their websites.
If you right click on the search bar, you have the option of edit search engines. There you can say for instance that the shortcut for wikipedia is wiki, so whenever you start a natural search with wiki in the bar it will fix wikipedia and search the next words in wikipedia. See the screenshots: