My bad to steer this thread off the topic... but since I said it I guess I need to explain too. Also note I said IE; Firefox has improved a lot on keyboard use, though it is still lagging behind Opera.
Primarily I mean that the keyboard has been a real consideration in the design of the browser with Opera. There are no annoying little mouse steps needed to do most things.
For instance, to get a new open tab, enter a web address and open that page, you just type (as quickly as you can, no pauses necessary) ctrl-n www.hometheaterforum.com enter and the page loads. This works reliably every time, no matter what the browser is doing. You can do this in mid-page-load if you want - the page you are loading keeps loading while you get a clean tab to load the new page in, no muss no fuss.
In IE, it's hit ctrl-n, wait until its loaded the page it was already on again, or bash escape until it stops loading - usually a bad idea, because it then starts loading another page from the hard drive to tell you it can't load the page from the internet (!) and after it finally stops churning, you still have to get your mouse cursor to the address line so you can click and then enter your text. I feel like I lose a year of life every time I have to sit there waiting... even though it may only be five seconds each time.
Opera has keyboard shortcuts for virtually everything. I don't even know them all, but the important ones I use a lot. Don't have the energy to describe them all, but they're at: