I was thinking the other day.
(Whenever I talk about how I was thinking sometime, I think of the 101 Dalmations animated movie. The two crooks, Horace and Jasper are sitting in their car, and the fat one says, "You know, I've been thinkin'..." The skinny one promptly bops him on the head, and say, "Now what have I told you about thinking! I'll do the thinkin' around here.")
Anyways, no, I don't want to tell you about a 101 Dalmations WPF (Windows Presentation Foundation) application that would be neat. It's actually a type of game. I think any game in this genre would be conducive to using the WPF framework.
And the winning genre is...Space Strategy. Also known as Explore, Expand, Exploit, Exterminate games, or 4X for short, these are the ones where you start with a home star system and expand with colony ships to other star systems, which you in turn use to gather resources and construct more colony ship, etc. etc. until you have a massive army and you annihilate the other players who are trying to do the same thing faster than you. Some of the more popular titles are the Master of Orion series, the Space Empires series, and Alpha Centari.
So why do I think this type of game could be well done in WPF? Well, they are mostly dialogue driven, and don't use any fancy 3D graphics. So if you made all the menus fade in with scaling effects and such that would be pretty cool. But besides looking cool, it would scale better to different size monitors. From what I've seen, the interfaces of these games have so many buttons and different things to click that they have a rather fixed arrangement. This would make things look significantly different on an ultra-high resolution, for example. With WPF, all your graphics would be vector based, and the game would be able to fill a large screen without running the monitor at a non-native resolution.
Also, WPF seems to be pretty flexible (powerful) with layouts. So it would be pretty easy to do customizeable toolbars, I'm thinking, or even something like the ribbon interface in select Office 2007 applications where the appropriate buttons come sliding in, depending on whether you have selected a planet or a ship. (You should see the menu in Space Empires IV. There are over 40 buttons on the top of the screen, always there. They do have a decent solution in that only the ones you can use at any given time light up, but there is always room for improvement.)
Whether such a game could actually be economically written in WPF I really have no idea. I imagine it would require a computer roughly along the lines of something capable of running Aero Glass to get anything playable. And whether programming such a beast would be fun (a lot of angle brackets for the XAML) is doubtful, but I suppose designing one in C++ is also not too exciting.
Just another idea I thought I would throw out there.