I personally really like Opera's MDI interface in general (note that they no longer have it in OS X, but the Windows and Linux versions still have it). Being a

I personally really like Opera's MDI interface in general (note that they no longer have it in OS X, but the Windows and Linux versions still have it). Being able to tile pages is nice, especially tiling vertically, what with the huge widescreen monitors we have these days and the way so many web pages have a small fix width. Yes, I know that you can achieve the same by opening up multiple windows and arrange them side by side, but if your operating system / window manager doesn't have good tiling abilities, this can be a chore, especially if you want to quickly switch back and forth between layouts. I wouldn't say that straight MDI is really ideal, I'd like to see some sort of split-pane type thing. Like Emacs, where you can arbitrarily split a pane horizontally or vertically and change what buffer you are viewing in each one. The buffers in this case being all web pages that are open. For extra points, because its probably technically difficult, being able to show the same web page in multiple panes would be cool; especially if you could do something like "Follow mode" in Emacs. This is probably not something with mainstream appeal, though.