I use Firefox for about 3 years now. I hated the tab system at first. But as soon as i got used to it. Its way loads neater rather than having 100s of windows mixed with the tabs of your other 100 programs running.
Firefox to me is still a Memory hog, although they made it better. It still chew up 500MB of resources easily with about 10-15 tabs.
IE is a shell of XP's explorer. Which is annoying but also poses many security risks. I think in vista that is why they they made IE seperate from the main file explorer. So It should be possible to remove it completely. But in the days of windows 95 where IE and the file explorer were sperate.
As for FF3 and 2.2 or what ever was the latest then

. Its alright, I have not really used the search multiple parts of the address in your hirstory. You know when you start typing in words, for example UnMarth, It might find the IRL to my profile page. It was a little annoying at first, But i haven't really used it to its full potential, I was woried it might slug down my system. But I am surprised it runs damn smoothly.
It has the save sessions by default when you close the window, which i want to get rid of. Its suppose to get rid of all histroy when it closes

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But FF3 looks promosing, more stable. But I still has frozen on me a few times. But not as often as 2.2