Either Safari or Firefox will work perfectly well, and you can have both installed, too.
Safari is always installed on each Mac and the icon – a blue compass – is in the Dock at the bottom of the screen. It’s the default web browser for OS X and as a result works perfectly well and is very fast, has a built-in RSS news reader, and shares the system wide dictionary and other OS X services, and more.
Firefox can be downloaded for free. It’s also fast, and supports tabs, like Safari, and works well on OS X and is regularly updated.
Each has fairly new versions, as of summer 2009: Firefox just released version 3.5 of their browser, and Apple released version 4 of Safari a few months ago. You need at least OS X 10.4.11 for Safari (along with a security update) and you can get version 4 and any updates through Software Update. You need at least 10.4 for Firefox, and the installer will warn you if you need a system software update.
Use the help menus in each browser to find out how to delete cookies and browsing history, use tabs, and find all the features of each.
One advantage of Firefox: it’s good for web sites that look wrong or don’t work at all in Safari. You see, Microsoft’s Internet Explorer is still the dominant browser (60-70% market share) and many web sites are designed to look correct in that browser with little regard to what the site looks like in other browsers, such as Safari (around 8% market share) and other browsers with even smaller market share, such as Opera, Camino and Google’s Chrome (not yet in final release).
So in many people’s experiences, if you are trying to use a web site for work or play and it doesn’t work with Safari – you can’t enter form data, register on the site, or the layout and design doesn’t apprear correct – Firefox can sometimes render a web site that is made just Internet Explorer.
In that respect, it can be helpful to have Firefox installed alongside Safari. If you’re having a problem with a web site in Safari, can cut and past a URL from Safari into Firefox and see how it works. But if you’re a casual web user and you’re not having any problems with sites in Safari, there’s no need to download Firefox.
There are plugins for Safari, too, but not very many, but they do give the ability to block ads, increase security options and more. See PimpMySafari.