Of course it's all personal opinion, but Firefox is the best to me too. I didn't like it in the early days, too different than what I was used to.
But once I gave it a chance, I've found I can't live without the add ons available. It's stable fast and it's said safer, although I never got a virus with IE.
I've tried Opera and Chrome, and I keep coming back to FF for the customization. It's the best to me, but again, up to the individual.