From drivers point of view what is better binary nVidia or Radeon open source that's my question, when i try Ubuntu in live mode it's start with 3D desktop effects on Radeon that's no can do on Geforce.
OS driver is also very stable and composition effects work excellent. 2D is very good too - I found resizing windows is smoother then in Vista when composition is enabled. However, nvidia drivers will give you excellent 3D and vdpau.
Ubuntu doesn't care about the radeon open source driver.
My laptop that has an older Radeon card and I only have the OSS driver option can't boot Ubuntu up without crashing. I have to boot up in safe mode. If I enable 3D, X crashes and it's not recoverable. There is no xorg.conf file by default so it has to be 'created' and then edited.
So, in short, a Nvidia card would be better in Ubuntu unless you know what to edit when you create the xorg.conf file.
Although I realize that the OP has made his decision already, I would still like to point out a few things;
1) There are many more distros out there than ubuntu. Fedora + Radeon-OSS is a real killer. Works very nice, just lacking a little video acceleration. 3D mode is unavailable by default, but easily installed with the mesa-experimental package. 2D is stable. I anticipate that the R600+ mesa drivers will be out of experimental and into stable by F13.
2) In consideration of long term usefulness of the hardware, Radeon is WAY ahead. You can consider that the open source drivers will be around for... ever, whereas nvidia could stop supporting any particular part at any moment.
3) The Radeon OSS drivers are *rapidly* improving. They're *great* right now, but there are MAJOR improvements yet to be implemented/completed.