at home I solely use IE7 - as much as I remember hearing how confuisng it was when it was first released, I honestly didn't think so. I was a little bothered by where they moved the drop down menus to, though . . .
but here at my gf's house, they use Firefox, and I've honestly never been happy with it - but, I think that has more to do with the person who set this computer up (my gf's mom's boyfriend), as he doesn't allow for any plugins to be installed at all - no shockwave, quicktime, flash player, wma or mp3 plugins. He didn't even realize that you can run IE7 from within Firefox, which is a nifty little trick when needs be.
But, to be honest, I prefer how IE7 displays webpages - but that's probably because 90% of webpages out there are still designed around IE.