Personally I use Firefox. I got times when I wanted to skip to Chrome, but after Firefox came with new version which fixed what I got problem with so yeah I am still with Firefox :D
Anyway I got Firefox, Chrome, Opera and IE installed because of web development.
Btw I saw interesting test somewhere. They were testing start up speed, loading speed of websites and battery consumption while those browsers are running. Intersting thing was that all those tests won newest IE 10.
IE did huge progress in user friendliness, support of standards and performance. Microsoft really started to work hard with it. Question is if it is not too late, because bad name which they made is just too strong.
Btw with safety and usage of modern technologies are all major browsers on nearly the same level. What counts for me atm is implementation of HTML5. Chrome got the best, but that is because of fact, that main designer of HTML5 is employee of Google (or something like that). Anyway it is not standard yet so I expect Firefox will reach the same level as soon as it will be out as standard (difference is already not that big).