there are three modern browsers

- IE9
- Firefox 4.0
- Google Chrome

No reason why you cant have all three of these installed on your machine. Pick one that becomes the default and try them all out. IE9 follows the web standards very well and also is very secure. But Firefox may be a better browser until the rest of the web catches up and makes themselves more compliant with the standards instead of dumbing it down to the IE7/8 level.