Glims

My major frustration with safari was that it could only support Google as it's search engine, and there was no way to change this without editing Safari's coding, a risky process that crashed safari if your modified version didn't have exactly the same file size as the original.

Enter Glims, a small app with allows you to add about 20 different search engines to safari and put them in order of your preference.

Other long-awaited features include:

• Full screen browsing 
• Undo close tab using Cmd-Z
• Favicons show at the top of tabs
• Thumbnails in Google and Yahoo searches.
• Session saving

If safari supported all the features that Glims provided, a lot fewer mac users would be switching to firefox.