Things like js-native games, heavy visualizations, such as the one on http://acko.net (his logo for example, otherwise take a look at his webgl renders)

Chrome also does better at hardcore number crunching, somewhere on the web, there's a demo webapp that tries to recreate images using procedural and genetic algorithms. I tried to find it, but I couldn't find it. Performance on Chrome however, is a lot better than on Firefox.