A good 160gb model being the largest capacity in that series would be the thought there. Presently I run a pair of WD 500gb sata models while planning to add at least one of the new Green Power 1tb model for that increase in storage capacity.
Any form of video will chew up drive space fast leaving a 74gb Raptor out uness strictly for the OS and softwares while using a larger second drive for storage. Some install games and apps to a second drive and then wonder why they have to be reinstalled later when swapping the host/OS for a new one.