Cross-platform, hardware accelerated, in-browser graphics plugin- Unity3D

Was working at a Panera Bread here in Redmond and met a startup founder who's working on some seriously cool collaborative filmmaking tools- with hardware accelerated 3D graphics within the browser.

As far as in-browser gaming, clearly this is a paradigm shift. Anything that has to do with high quality video, clearly a big win. A true in-browser photo editing program could also be pretty slick- cloud-based Photoshop and Illustrator competitors are feasible, sans all the slowness that Flash-based editing apps bring forth. Higher quality music visualizations are a no-brainer.

That's off the top of my head, what else comes to mind?