I only have minimal experience with Ubuntu - I was running 8.04 on a spare computer just for fun. I tried to install 10.10 on my main desktop and experienced the same symptoms as fanf42 - blank and flashing screen. As the install cd began booting, when it gets to the point where you can choose "Try" or "Install," the screen flashes on for about a second, then goes blank (black) for about 5 - 10 seconds before it flashes again, but the time in between flashes is random.
I have an ati Radeon X1600 video card w/ 512mb ram and an Acer P244W 24" widescreen monitor.
The problem only seems to be with the DVI connection - not with the VGA connection.
While trying to troubleshoot the problem, I connected an older Samsung monitor (15" non-widescreen) with the VGA connnection (that's all the samsung has available) just to see if the problem was with the monitor, and sure enough, every thing looks fine after rebooting the Ubuntu install cd. I was able to "Try" Ubuntu by running the live cd - everything looked great.
My next test was to try the VGA connection with the Acer monitor instead of the DVI (the Acer offers both connection types). Once again the flashing and blank screen went away. I was able to change resolutions while running the live cd. It defaulted to 800x600 - I changed it to 1024x768 (this was the only other resolution available on the live cd.)
So now I hesitate installing Ubuntu 10.10. I don't want to have to change my video cable to VGA.
Last point is this would be a duel boot. I'm currently running XP sp3 with no video issues.