It's worth a couple minutes of your time to pitch to a .org, particularly if its a heavily frequented site (see complete.com), has a large endowment, or is backed by a for-profit group.
So far I have been able to sell my domains to non-profits for $150-250, individuals for $250-$350, and small businesses for $450-$650 with little negotiation. Non-profits are generally the lowest-paying genre on the spectrum, but they'll punch holes in their pockets if the domain you're pitching them is relevant and significantly better than their own.
For example, today I sold a three-short-word non-hyphenated .com name to a small NYC outreach organization who owned the hyphenated version of the .org domain. I asked $400, they countered with $150, and we ended up settling for $250. Not bad for 10 minutes of my time.