Gingerbread is coming to the Nexus One for the first time while Nexus S owners will be getting a few additional features and bug fixes in the 2.3.3 version. Google plan to send out the update over-the-air (OTA) sometime in the next few weeks.
There are a few key developments that will make a noticeable difference:
Unfortunately there is also a downside, as the update will disable the integration of Facebook contacts for Nexus S users. Why they have done that is a mystery, but probably a worthwhile price for all the welcome bug fixes.