Opera is my fav..Fast,Secure and Clean Thn there is maxthon..free too !(http://www.maxthon.com).the engine is the same as IE but it has some cool features like adblock and all..I use it for some IE sites and also needs less resources than Opera..
I made the switch to Opera just a few weeks ago, and am very satisfied with it. It's got a few nifty features which I like a lot (mouse gestures for instance). I haven't tried Firefox. I have IE still installed as backup.
I like Opera. After M$ trashed Netscape I was eager for anything better than M$ VirusExplorer 3.0 . Tried Firefox, could just be a cultural problem, didn't like it. When Opera crashes- two or three times a day with 15 or 20 tabs open (I have a gigabyte. Don't try it with less...) it pops back up with one clicki faster than FF or IE. Neat! Clean History by >Tools | Preferences | History | >clear< >clear< >OK< then hit (XP Pro) >Page< | >Settings< | >Taskbar and Settings< | >Start Menu< | >Customize< | >Clear< | >Ok< >Ok<