Re: "All Good Things" ... an exciting thought...
Yep. I think the Season 3 screening will feature Yesterday's Enterprise and Best Of Both Worlds Part 1.
If the past two screenings are any indication they've shown an "action-y" episode (to show off the new effects) and slightly more dramatic episode that's less effects-heavy. For S3 I'd expect to see "Yesterday's Enterprise" for the "effect"/action episode and either "Sarek" or more likely "Offspring" for the less-effects oriented episode. At the very least they won't show BOBW likely because it IS a two-parter. (Though it could be argued they'll show it and then show BOBW2 for the S4 screening.)
For me, and for many of us, the future is now in the past.