By popular demand, here in the link to installers for Chromium on Windows:
While Google explicitly does not support the Chromium web browser, they have in the past indicated that developers might find it useful. I like to run it on both my work and personal machines rather than the consumer edition of Chrome because (a) it is completely open source and (b) I believe it is more privacy-friendly.
These developer builds are in both 32 and 64 bits.
The 32-bit versions of these binaries are recommended over 64-bit as more stable.
Also keep in mind that, as far as I know, there are no 64-bit Windows versions of popular plugins like Adobe Flash or Acrobat Reader.
 Mozilla also generates a 64-bit nightly build of Firefox for Windows. Neither Google nor Mozilla have ever shipped a general release of these Windows products in 64-bit. See this article for an update from a Mozilla spokesperson.
 See this extended comment for more.
 It took Adobe over three years to release a 64-bit version of Flash for Linux, once they got serious about it. The long, difficult, saga of that effort is preserved in the PenguinSWF blog.