I'm looking to buy a new 21.5 iMac. I like the size and my external monitors are already that size so 27 isn't really an option. My one problem is that with the 21.5's, the highest storage capability is 1TB. On my old iMac I already have that totally filled and I'm getting more and more film projects coming my way so I need much higher capacity. Basically I'm looking for an affordable, effective method of keeping my video files on external drives. I'm a student so really the max price I can afford is about 500-700. I would need probably between 3-4TB's (more is better though obviously) and if there is some sort of redundant raid system available that's a plus. I'm editing on Premiere Pro and After Effects CC. Suggestions?