After the usual 6 months of development, Ubuntu 11.04 has finally been released.
A message on the Ubuntu devel mailing list mentions that the current state of Unity will be brought up for discussion and if needed, the Classic GNOME Desktop may be default after all in Ubuntu 11.04:
Since a lot of people want to upgrade to Ubuntu 11.04 Natty Narwhal already, I though you'd like to see a video (well actually 2) on how to upgrade to Ubuntu 11.04. Remember that starting with Ubuntu 11.04, you can upgrade using the Live CD too.

In the above Unity video you'll notice:
The "ubuntu-wallpapers" package has just been updated in Ubuntu 11.04 Natty Narwhal and it now includes wallpapers from the Ubuntu 11.04 community contest:

Remember Borderless Elementary? It was quite a success and I'm not sure if that's where the Ubuntu devs got the idea from, but update today in Ubuntu 11.04 removes the borders for the Ubuntu "Light" themes:
Unity 3.6.4 was uploaded to the Ubuntu 11.04 Natty Narwhal repositories a few minutes ago, brining some features many of you were waiting for. Read on!
Do you use the Compiz Desktop Cube plugin? I don't use it so I didn't notice this but it seems you can't enable the Desktop Cube in Ubuntu 11.04 if you use Unity - a bug about this has been submitted but it was marked as "opinion" so it doesn't look like it's going to be fixed, at least not in Ubuntu 11.04:

Christian Giordano has announced that Unity will get overlay scrollbars. This means the scrollbars will not be visible until you move your mouse over the side where the scrollbar used to be.

With a slight delay (of almost one day), Unity was updated to version 3.6.0 in Ubuntu 11.04. This update doesn't bring major changes but it fixes a lot of bugs making Unity a lot more stable. You can check out the full Unity 3.6.0 changelog, HERE.
An update to the Ubuntu 11.04 installer (Ubiquity) finally brings upgrade support to the Ubuntu Live CD. That means that for instance if you use Ubuntu 10.10, when you'll boot the Ubuntu 11.04 Live CD you'll have an option to upgrade (without losing your documents and installed applications). Besides this change, there's also a redesigned partitioner:
A new Compiz-based Unity version (3.4.6) was uploaded to the Ubuntu 11.04 repositories minutes ago, getting one of the features you've just seen in the Unity 2D video we've posted earlier: when pressing and holding the Super key, a number is displayed for each application in the Unity launcher and pressing that number will launch / raise that app.
Unity 2D (Qt) is finally getting closer in design to the regular Unity. Check out this video recorded by by om26er:
Andrea Azzarone, who's also behind the menu integrated in the window titlebar Unity mockup we've posted last week has created a patch that provides an option to change the Unity launcher ("dock") icon size.
Check out this video featuring his actual code (not a mockup!):
The Ubuntu devs really like to push updates at night but luckily I'm usually awake when that happens so I can tell you what's new in Unity as soon as the updates are released.
One of the design goals of Unity is to reduce the clutter of the desktop, another is to use space more efficiently.