There was a He-Man movie?!?!?!?! :O
Lankhmar - yeah, that was a campaign, too (interesting roguelike campaign, but a bit small-scale (mostly just the city of Lankhmar, I think).
Forgotten Realms and Greyhawk were sort of similar as generic AD&D campaigns, but FR was always very specific (with lots of material), not leaving much for the DM to decide; Greyhawk was always the opposite (quite a lot was left open for the DM). Also, during the 2e era, I guess that FR was the most widely supported campaign setting.
As for 1e vs. 2e, I think that manikus's approach is fine
Changes mostly included:
1. Rule changes to match 2nd Edition (no more monks or half-orcs, bard, ranger, illusionist classes changed, specialty priests/specialty wizards added, etc.)
2. Later, specialty priests were fleshed out more (more abilities, different XP tables, etc.) and new optional classes were added (harper, etc.). The crusader, monk (2e monk), mystic, and shaman were also adapted.
3. Kits were adopted and added to.
4. Changes in story (and maps) - i.e. Zhentil Keep destroyed, Bhaal/Bane/Myrkyl/Leira/etc. killed, new gods Kelemvor/Cyric/etc. appear, old gods reappear (Garagos/Istishia/etc.), etc.
...but most things are basically the same.
