If you think the Google searchbar in Safari is a bit limited I recommend you install a Safari add-on called Glims.
Search Engines
Glims lets you change the default search engine used by Safari’s toolbar search field.It comes with predefined sets of engines and, as expected, you can define your own from the preferences.
You may also want to see:
Adding a new search engine to Safari
Defining keywords and shortcuts for search engines
Site specific search definitions
Search Suggestions
Glims provides search and link suggestions while you type in the search field. This is very similar in concept to what Apple introduced with Safari 4. The cool thing about Glims is that you can define which sources you would like to use for the search suggestions. Among the obvious benefits, this will come in handy if you are not located in the U.S. We plan on doing a lot of improvements on this module for future versions.
Google/Yahoo Thumbnails
Glims adds thumbnails to Yahoo and Google Search’s. Again, all configurable from the preferences.
Tab Management
The two main improvements are the favicons in the tab bar and the restore of the tabs at launch. Since we are using Apple’s session manager, the tabs are currently stored without history, but we are working on this. (Not sure exactly when it will be available.)
Other improvements include; force new window to open in tabs, select the placement of the new tabs when created (right,left,…), undo close tabs… (you get the idea).
Bookmark Bar Improvement
We added bookmark separators, as well as ‘Add folder here’ and ‘Add bookmark here’. This helps when you want to manage your bookmarks directly from the bar.
Other Improvements that are also configurable from the preferences:
Full Screen – Basic full screen functionality accessible from the menu or shortcut. Again, we want to improve this.
Max Window Size – Spread the window on the whole screen, accessible from the menu.
Form Autocomplete – Force the auto completion of forms in sites that prevent it.
Dated Download Folders – Organize your download folder.