Chrome: Most new features that are added to the dev channel of Chrome aren't worth trading the stability of the regular or beta channels. The addition of Google Now is potentially an exception.
Google Now cards have been added to desktop Chrome by way of the dev channel. Tied to your Google account, the cards offer many of the same features such as traffic, stock updates and sports scores that we've become familiar with on mobile devices.
Even if you don't want to risk using the dev version (where bugs are part and parcel of the experience), its appearance is a strong indicator that we'll see it soon in the beta and stable channels. If you want to try it out right now, though, just install the dev version of Chrome or, if you're already using it, update your browser.