The short answer to the Firefox safety question is, "Well, yes, but..."
The longer answer is that out of the box (i.e. freshly installed), Firefox isn't really any safer. Like Internet Explorer, Firefox is prone to its own share of security vulnerabilities and exploits. However, if you add the free NoScript addon for Firefox and you disable Firefox http header refresh, Firefox becomes much safer than Internet Explorer or any other browser.
Part of the reason that firefox is more secure, is because it doesnt support active x the same way. Hence, websites cant take control of your computer that same way.