I had to give up on Opera due to a few little annoying problems.
I'm now back on Firefox and have installed the following add ons to make it look and feel far more responsive.
SmoothWheel for super smooth scrolling.
Fasterfox for improved speed.
Download Statusbar for improved download window.
Socool which is a theme i like.
I had tried to change to Google Chrome but only lasted a few days as i hate the tabs on top.
Opera is looking to be a very nice browser but it's a shame pages aren't displayed correctly like in other browsers.