Opera. Offers tabbed, non-tabbed or a combination eg you can have an Opera window open with tabbed pages & have another Opera window on the go as well.
I usually use a single Opera window with ~30 tabs running. While one or more is/are loading I view one that has already completed. Once finished I send the current tab on to its next target & start reading a different tab. Works really well.
Standards compliant so any site that is written to W3C standards works. There are relatively few sites that require IE. They're usually poorly written with broken or strangeM$ specific code. Thank christ most work. It a real wrench for the worst to have to use IE.
Opera loads faster, is more secure, offers much greater control over cookies & pop-ups etc etc.
Areas to improve:
Access to cookie controls. It's a bit cumbersome & not very intuitive at first.
Bookmark/favorites (sic) management. Somewhat easier in IE.