Nearly all Intel video cards have open source driver and therefore work fine under Ubuntu, however, I would like to know which are the ones that don't? I want to buy a laptop and need to know which cards should I watch out for. I am not considering Intel cards that have closed source driver, I would be better off with NVidia then.
The only recent Intel GPU with a proprietary driver is the GMA500 (Poulsbo) chipset found in some Atom based devices. Unlike Intel's other GPUs, this chipset was based on the PowerVR GPU.
Anything based on Intel's own designs should be supported by the open source drivers. If you are still unsure, you can find a list of the currently supported chipset names on their web site: