Yesterday Google announced 64-bit version of Chrome. If you want to get one, you have to choose between Dev Channel and Canary channel for Windows 7 and 8 users.
I dare to suppose, that 64-bits builds of browser soon or later will be moved to the beta stage.
According to the developers, new version of Chrome is about 25% faster than the regular one. Furthermore, browser supports some features of Windows 8, for example High Entropy ASLR, which makes browse just a little bit safer.