Basic DND (Holmes): It was my introduction although I only played it for a week.
- Modules B1, B2, X1
- Gazateers 1-14
1e: The edition that got me into the game. It introduced me to the Demon Princes and Arch Devils, beholders, drow, kuo-toa, and mindflayers.
- Several Modules: C1, D1-D3, G1-G3, I1, I3-5, I6, N1, L1-L2, Q1, S4, T1, U1-U4, WG4
- 1e Forgotten Realms
- FR 1-16
2e:
- Cleric Spheres
- The settings: Al Qaudim, Darksun, Ravenloft
- Kits: good idea, but the patchwork mechanics of pre-3e DND made many of the kits wonky
- Complete Thief's Handbook
- Viking's Sourcebook
-PO: Combat and Tactics
- PO: Spells and Magic: I like the spell point system and variant styles of magic based up on it.
3e
It brought me back into DND.
- Unified Resolution
- (edit) Unified Experience chart
- 3 Save Categories
- Skill ranks are purchased
- the breakdown of skills (except for Use rope).
- Removing Race and level restrictions
- 0/0 level multiclassing (3.0)
- feats. Although, imo, several of the combat feats could have been standard maneuvers.
- Higher AC is better
- Monsters have stat bonuses
- the customizing a character section in the PHB although I would have liked to have seen elaboration.
- Unearthed Arcana
- OGL and d20STL allowing 3rd parties to play with the system. Without the 3pp support and their material, I would not have stuck with 3e.
- MM2, Fiend Folio, Fiendish Codex I, Lords of Madness, Dragonomicon, Stormwrack Stormwrack, Heroes of Horror, Book of Vile Darkness (as a DM resource).
4e
- Removing most of the nonbiological aspects of race and making them feats. This is one of only a few things from my pre-3e questionaire feedback that did not make it into 3e. I would love to see a 3pp do this for 3e.
- Armor proficiencies, weapon proficiencies and save bonuses for a classes are bonuses only apply at to first level characters. This was already a house rule of mine.
- Class based defense is official another one of the few things from my pre-questionaire feedback that did not make it into 3e. Maybe somebody can adapt this to 3e.
- Unified Save progression
- Action point are core even if I don't like the 4e mechanics compared to other mechanics I have seen for d20/OGL games.
- Passive Percepton. Already a house rule.
- spellcasters are balanced, but I still dislike per encounter and daily
- trimmed back the "Christmas Tree Syndrome"