There's no word yet on what exactly is causing it, but various Google Chrome users are reporting that searches from the omnibox / address bar that go nowhere. While the instant results appear properly, once the user hits enter they're sent to a blank.html page that's just that, blank. There's a Google Groups thread 116 posts long of people noticing the issue going back a few hours and we're seeing it on our end also. In the thread, users suggest going into the settings menu, selecting "Manage Search Engines", adding a new search engine with the url http://www.google.com/search?q=%s (it can be named anything) and then making it the default as shown above. That did the trick for us, let us know if you're seeing the same in the comments below.
Update: Google has responded, telling us the issue should be resolved for "most users." If you changed your default search, this would seem to be as good a time as any to switch it back, check after the break for a statement from a Google spokesperson.