Here's how I use browsers on my PC with Vista:
1. Internet Explorer - this is my workhorse for complex or risky pages, but the security makes it fail to read good pages often
2. Firefox - used to be my favorite - and still is my default browser where I need rich functionality on complex pages, but it's a bit slow because I use add-ons
3. Opera - this is my latest and favorite browser - it has all of the features I use in Google Chrome and is much more robust - it's on release 9. It's faster than Firefox or IE - so I have that open in a window for quick research and rapid news scanning. I like the way you can type a search term into the URL field - as you can in Chrome. I like the default page with miniatures of my favorite pages.
4. Safari - I tried this and it's about the same speed as Opera - I use it on my Mac and iPhone as the default browser - it reads most pages - but it's not compelling.
5. Google Chrome - is a work in progress and lacks features. I understand simplicity, but it's just too minimal. I had to add a "send link in the mail" script -I can't believe that this is still not a standard feature. I hate using the email buttons on pages as they don't have names from my address book pre-loaded. So I always send the link in a browser - sometimes running it through a program that shortens the link.
Someone asked me if the browsers interfere with each other - the general answer is no. However, if you have too many windows open and a lousy graphics system then the system may freeze until you close a window. Another situation can arise where two browsers want to use the same file and it's locked - but that's a very, very rare event - it's only happened to me once.