Since 2002 I've used an Internet Explorer enhancement/replacement called Maxthon which even back then had tabbed browser windows. If you've worked with Firefox or IE7 (and I'm sure other browsers), you'd know how useful the tabbed interface can be.
Maxthon added a whole lot of other stuff over IE, but I mainly used it because of the tabs.
The other day I came across Terminals, a Remote Desktop enhancement/replacement that presents Remote Desktop sessions in a tabbed interface. It too does a whole lot of other stuff to help manage multiple connections, but tabbing is IMHO the most useful feature.
(If you check out Terminals, make sure you grab the latest source build which is currently at around version 1.6 from http://tools.mscorlib.com/)
In both these cases, the tabbed interface is almost "the" feature rather than just another feature.
I reckon the Windows taskbar needs to be rethought if the simple concept of grouping like windows together can't be done without enhancements like Maxthon and Terminals. It seems to be easier to train myself to use ALT-TAB like a keyboard ninja, rather than mousing around two monitors looking for my open program :-)
On the other hand, tabs make sense within programs to group "documents", so perhaps the the taskbar should be left alone, and individual programs' handling of multiple documents improved.
What's next - tabbed Word? Tabbed Outlook? Tabbed Windows Explorer? Hmmm...
UPDATE 7/Aug/2007: Fixed title to remove ampersands.
Tags: user interface, terminals, remote desktop, tabs