(1) Is it true that the new GUID Partition Table scheme allows a user to partition a drive however he/she like, outside of the traditional MBR "4 primaries or 3 primaries + 1 extension" paradigm? If so, are there any limitations to the GPT? If my assumption is wrong, what are its advantages over the MBR model?

(2) I'm getting a new laptop this week and will be installing Ubuntu (and, more generally, Linux) for the first time ever. Does Ubunutu come pre-configured with MBR as a default? If so, how do I get Ubuntu w/ GPT? If not, how do I specify GPT over MBR?

Thanks!