This is not gonna be a question for long but more a battle of IE vs Firefox(Mozzlia)
I have both on my machine!
(I'm Running Vista)
This is what i have decided to do!
Use Both! - There is an add-on for Firefox called IEtab, this allows you to instantly switch between a firefox rendered page and an IE rendered page
So you just always run firefox, and when a website that needs IE(there are some but they are dieing) then you can click the icon and instantly change without opening new windows, ect.
You can get Safari for Vista......i'm not sure, Mac-ware on a Vista computer, sounds dodgey to me.
Although i have got into the habbit of running IE7 now because its logo is better(i can find it much quicker :P )
Additionally - Don't listen to most of the Firefox freaks who don't realise that IE7 has Tabbed Browsing......Their just addicts.
IE7 is stuck on your machine no matter what and is needed for accessing Windowsupdates via web-browser.
Active X - This is Microsoft's homegrown, any webpage that uses this is going to give Firefox/Safari a hard time, IE will breeze it!
IE7 Vs Mozzila On a Security Branch? - seems that firefox was always better than IE6, but vs IE7, its a new ball game. realistically speaking, both are now extremely tight on security issues.
Firefox has proved faster than IE7, but not by far.
Firefox proved faster than IE6, by a hell of alot.
My Summary would be:
-Lazy - IE7
-Not so Lazy, Firefox with IEtab