The problem is that Unity and GNOME 3 are made to have nothing on the
desktop and anything that runs gets its own workspace and does not go to the
system tray (which is gone) or the desktop which kept clean. So things like
widgets and gadgets are not going to happen, IMO. I could be wrong, they
could bring them back if there is a demand or losers drift away.

If you want these things then you may have to switch to something like Opera
gadgets which are independent of Opera once installed. But they would not be
a gadget any more but would have its own workspace. I don't think they have
weather radar, but do have weather applets. I run Kubuntu and have no
problem with widgets, but Ubuntu is going to be a problem whether you choose
Unity or GNOME 3 even if you could find a binary file or compile from
source. I have similar problems and wonder whether things that run from the
system tray will start disappearing, too. I can still install them and run
them in KDE which still has a system tray, but am worried that they will go
the way of Google Gadgets. Every release has a few casualties. An
application that I miss is Klibido for downloading binary files from usenet.
I am using Pan but do not like it. :(

This brings up the subject of Natty. Do not upgrade to 11.04 if you are
happy with what you have. Wait a bit and read up on what the changes will
mean to you.