VM or Boot Camp Partition?

I'm shortly going to be getting a new system (probably an iMac, but maybe a Pro) and was wondering what the best setup is for running Parallels. I've been thinking the best choice is to set up a Boot Camp partition, so that I retain the option of rebooting natively into Windows, but can still run in all the various Parallels modes. Other than the portability of the VM setup, are there any additional benefits I'm not considering? Which method will run faster? Is either likely to give fewer hardware issues?

 

I've got Bootcamp on my new iMac and Parallels on my MB. They both run fine, but I'm guessing if you want full power, the Bootcamp option would be better (all memory to Win7).