Safari needs Saft
If you are an avid Safari user, you're going to want to purchase
Saft to fully trick out your browser of choice.
Saft version 7.5.5 has just been announced and has a long list of useful features for a single Safari plug-in, including full-screen browsing, searchable bookmarks and history, URL shortcuts, kiosk mode, and
(my absolute favorite) crash protection and tabbed browsing memory. This means that if you accidentally close out Safari with 5 different tabs open, simply relaunching opens up all the tabs you were using in your last session.
If you install the demo, Saft will give you a warning every time you launch Safari, telling you to purchase the full version. I used the demo for about a week before I dropped the $12 via PayPal to grab my copy. That was a year ago and I've never regretted the choice.
Sure, some of these features are built into Firefox or available via plug-ins for free, but so far I
haven't seen a solution, free or otherwise, for the little OS X nuances that Firefox lacks and which make Safari my preferred browser.