You’ve gotten some very good advice here, as usual. I’d like to add is my hearty endorsement of creating an Off-Line with that 250 hours – and 2 cents more.
You can do the off-line in FCP or an even better option, to my way of working, is to use CatDV. It’s fast, searchable and works seamlessly with FCP. It’s ability to keep your notes and timecodes together – and searchable – is a huge timesaver when working with so much material. As for storage, I’d stay away from anything but pro gear, and CalDigit is always my first choice. Their drives, cards and support can’t be beat. If you’re in SD, you don’t “really” need a Kona or the like, but it’ll make your life much, much more pleasant. You will need a better monitor for color work and unless you like squinting, 20″ won’t make it. Especially after a slew of 18 hour days. If the director is sitting with you, you’ll need a second screen for sure.
I’ve worked on several docs with similar requirements and this workflow: CatDV, or even FCP if you’d prefer, in lo-rez off-line, save the final color and efx for the on-line [you can make a start with the off-line], CalDigit drives [call Jon and tell him what you’re doing and he’ll get you into the right one], a fast machine with plenty of RAM is the way to go. A Kona or Blackmagic if you’re flush will make any up-rez or add’l monitoring needs simpler.
Anyway, them’s my thoughts. Good luck! Sounds like you have an awful lot of notes to take.