Thanks to all who replied to my last post, both on DW and LJ, I have a list-in-progress of must-see episodes that fall after The Armageddon Factor. Plus I've added a couple based on things I've seen/heard or because they're the first/last story for a Doctor, because it only makes sense to me to see their first and last stories if nothing else. Plus I threw in The Two Doctors just in the interest of seeing all the multi-Doctor episodes. Here's where it stands now:
Fourth Doctor
- Destiny of the Daleks
- City of Death
- Warrior's Gate (n/a through Netflix)
- The Keeper of Traken
- Logopolis
Fifth Doctor
- Castrovalva
- Black Orchid
- Time-Flight (unavailable)
- Mawdryn Undead
- Terminus
- Enlightenment
- The Five Doctors
- Warriors of the Deep
- The Caves of Androzani
Sixth Doctor
- The Twin Dilemma
- Attack of the Cybermen
- The Mark of the Rani
- The Two Doctors
- The Trial of a Time Lord (which is apparently 14 episodes!)
Seventh Doctor
- Time and the Rani
- Dragonfire
- Remembrance of the Daleks
- The Greatest Show in the Galaxy
- Battlefield
- Ghost Light
- The Curse of Fenric
- Survival
Eighth Doctor
- The Movie which seems to be universally regarded as craptastic, but doesn't really seem skippable
- books/audio of some kind
Um, yeah, considering most of those are at least 4 episodes and one story is an entire 14-ep season, that's quite enough of a list to try and get through by November! :-D
Thanks, all, for the suggestions!