For anybody that doesn't like Opera, try Mozilla Firebird - it does tabbed browsing and is pretty fast and light.
Mac users have even more choice. As well as Opera and Firebird, Safari 1.1 (included with OS X 10.3) does tabbed browsing very elegantly, is fast and highly standards-compliant.
The only problem with all this talk of tabbed browsing is that it isn't good for the server to have to supply you with several pages at once. I doubt enough people are using this facility to make it a problem. Watch out for some plug-ins though; they allow you to download every link on a page into individual tabs with a single click. Several people using these at once would be bad news for everyone.