OK, with the testing out of the way, what conclusions can we draw? Well, overall, IE 9 32-bit topped one test, and Chrome 15 topped the other three, so overall it's fair to say that Chrome 15 is the winner. But when you take a deeper dive into the data, things aren't that clear cut. For example, when it comes to the SunSpider test, the five browsers are separated by less than 60 milliseconds. What's more, little over 10 milliseconds separates Opera 11, Chrome 15 and Firefox 8. This could have been anyone's race!
Other tests are more clear cut. Chrome 15 was the clear winner of the V8 benchmark test (bear in mind that the V8 is a Google benchmark). Chrome 15 also wiped the floor with the competition in the Kraken 1.1 test too, being nearly twice as fast as the nearest rival Firefox 8 (which itself was almost twice as fast as its nearest rival).
Also, given how well IE 9 performed in these tests, sticking with the default browser that comes with Windows no longer gives you an inferior web experience.