Ah! Found one! I knew there'd be another post with my problem. Problem is, there's no solution!
So, I also have an Nvidia 8800GT and am having this exact problem. It comes to this point after no problems with the splash screen or other drivers, flashes 3 times, then brings up the classic 'X' cursor on a blanked screen, then brings up an Ubuntu window stating
Ubuntu is running in low-graphic mode
Your screen and graphics card could not be detected correctly. To use higher resolutions, visual effects or multiple screens, you have to configure the display yourself.
Then there's a selection box where you can check "Always run in low graphics mode"
and three more buttons: "Configure...", "Shut Down", and "Continue".
The configure screen lets you manually pick your monitor, resolution, and graphics card. However, any route I take through that OR simply hitting "continue" end up right back at the same spot that the original post shows with his attached picture. It just sits there. I have the ability to switch to other windows (ctrl-alt-F2 etc), so the computer isn't hung.
I've also tried booting in with safe graphics mode, but that ends up with a failed boot into some sort of busybox thing.
Anyone with a solution?
Don't make me go back to Vista! Please!