to be frank, I use both IE and Firefox (Firefox is most preferable). From webmaster point of view, I need to test that website looks good in these 2 main browser.
Hi, As per mine Firefox 3.5 has lots of User Friendly features. That's why mine vote goes to Mozilla Firefox.
I would say different user would have different requirement and thus the best browser is depending on what the need and requirement. web Developer and savvy IM who need flexibility (like adding various useful add-ons) that will help in their work would most probably prefer Firefox. Normal user who just want to surf internet may prefer IE / Google Chrome /Opera, etc. Some normal user may prefer Firefox with their fancy browser skin which can be easily changed. There are certain groups of people who just like out-of-the-box default software/settings in their PC will choose IE, as that's what pre-installed in the new PC.
In my view firefox is the best browser I have ever used. It has many features like speed dial, tab system, etc.
Desktop : I would have to say firefox. Mobile: I highly recommend you check out skyfire for your devices, Has flash and runs smoothly.