The amount of space isn't so impressive, but the physical size and number of spindles.

I worked at one place that had 3 100tb disk arrays, each one was spread over 15 racks, giving 3gig a second throughput. (in 2007)

Now, 170 tbs, and a server fit in 5u. 60 disks give 2gigs(bytes) a second throughput. 2.5 racks gives you 5.5PBs and ~60gigabytes/second peak (25-8 sustained)

RED is Hollywood-class, though towards the lower end. A lot of big-name movies that you've heard of include scenes shot on RED cameras: http://www.red.com/shot-on-red. The TV show Leverage was shot entirely on a pair of RED Xs.

RED's stuff is on the order of $25k. The main player for digital cinema is Arri ALEXA, on the order of $50k. It's not that far off.

Yeah I've read big names switching to RED (that's what made their business thrive). I was also referring to the disk space. A single person can assemble a 100TB setup. That was Pixar territory not long ago.