I am logging using the jQuery.log plugin (which logs to console.log if available) and I am not seeing any of the logging messages appear in the Chrome JavaScript console.
I am not sure if this is the case, but if you are using firebug with chrome, you have to turn firebug off in order for console.log() to work in Developer Tools.
When playing around with example Chrome Extensions, I was often unable to see the console.log messages when looking at console (ctrl+shift+j). But then I realized, that I was in the wrong place.
Wrench -> Tools -> Extensions and then click on the appropriate link under "Inspect active views". (in the Chrome examples it is often background.html) This should bring up the console that you are looking for.
On my computer I had accidently clicked the Debug filter. This made my log messages hidden. Here's how it was before (hidden messages):
Here's how it was after the change (working messages):