Boot Drive (no photos, only apps and OS X)
"Sean" 160 GB
RAID 1 (all of my files, including photos docs, movies, music)
"Pierce" 320 GB
"Daniel" 320 GB
Ext. Backup 1 (backup of all files)
"George" 500GB
Ext. Backup 2 (backup of some files, now dead)
"Timothy" 100GB
TOTAL 1300 GB or 1.3 TB
You shouldn't need 2TB of space, unless you're leaving a lot unoccupied (which is smart, considering the golden size right now is either 500 GB or 750 GB). I'd estimate that, with a relatively light shooting schedule (avg. 200 photo/wk school year, 75/wk summer), I only have 40gb of photos over the past year (plus about 20 from previous, even lighter years).