Internet Explorer now has tabs.
You can get them by installing the MSN Toolbar, which should also give you the fantastic (yes, I a truly wonderful Microsoft product, even it it based on Lookout) MSN desktop search.
I’ve only just installed it but it looks okay so far.
The tabs are workable, but feel clunky compared to Firefox.
The Search however, I love. And unlike Google desktop search, it works with my virus scanning software (Vet).