Have to agree with wolfie3000. I've tried them all and have found fault with most BUT for sheer speed ease of use and customisation I couldn't beat Firefox. Having said that IE8 came a very close second.
ie8 if you want omething thats ok straight out the box
chrome was too basic for me, but its what some people want
i vote firefox because some of the addons make interneting so much easier reccomended addons, -a favourite theme -WOT -image uploader -IE tab -spell checker -sidebar -flash video downloader -MOST IMPORTANT- adblock
Fast and, unlike Firefox, complete, so not in need of myriad addons. Opera have also done a good job of implementing tabbed browsing, an area where Microsoft have failed dismally since they first introduced tabs with IE7.
I spend my day working with IE6/7/8, Safari 4, Chrome, Firefox 3.0 & 3.5 beta, as well as Opera 9.6, and Firefox 3 beats them all for all-round ease of use, flexibility and features. Safari and Opera are good in parts but have some annoying quirks.
The about:config interface, excellent cookie management and range of add-ons (including some that are invaluable for my work) make it really easy to tune. It's the most usable browser over all, so it's my default choice.