This post is for Apple OS X users. This is a nice trick for setting Google Chrome Canary as the default browser in your OS X. You can’t do this within Canary itself. Since this is a nightly build edition of Chrome browser, the developers have intentionally disabled this feature. So to have Canary as your default browser:
Click on Preferences
Under the tab General, choose Google Chrome Canary as the value for Default web browser
That should do the trick!
Update: Since this post is getting quite a lot of attention I figured I should update this with a cautionary tale. You should know the Canary is an unstable and untested build of Google Chrome. When the browser gets updated behind the scene, you may be introduced to a few bugs. One such bug deleted all the links in the Bookmark bar! And since my bookmarks are synced across browsers and devices using Xmarks, I lost the bookmarks in all my browsers in all my machines! I launched Firefox and watched the links disappear before my eyes and cried out in horror! Fortunately Xmarks keeps backups of your links in the cloud, so I was able to download the backup files and restore them. But I stopped using Canary since then.