Well, there has been no topic asking people which browser they use and why since the board came back, so I guess I might as well. 
Personally I like Opera. I've used it for a long time now and just can't go back to either Firefox or Internet Explorer. The major benefits with Opera include all-in-one program, the powerful tabs system, the vast amount of shortcut-buttons, the notes system, allowing my to chat in IRC while I'm browsing, and the very low usage of system resources - much lower than Firefox.
Since Opera 8.5, there have been no advertisements which in my opinion is just an added bonus to use it.

Personally I like Opera. I've used it for a long time now and just can't go back to either Firefox or Internet Explorer. The major benefits with Opera include all-in-one program, the powerful tabs system, the vast amount of shortcut-buttons, the notes system, allowing my to chat in IRC while I'm browsing, and the very low usage of system resources - much lower than Firefox.
Since Opera 8.5, there have been no advertisements which in my opinion is just an added bonus to use it.