My pick : 2nd edition. I like the others as well, this is just my favorite.
Why? It matches most closely the type of fantasy feel I enjoy.
Case 1: Oscillating challenge. Or as I like to call it run from the wolves defeat the bears. Later systems are more balanced and have more guidance of how to pair the characterizes with level appropriate challenges. In previous edition that was not a given and it was up to the players to decide whether to make a stand or run. A group of 9 level character can be facing a group of gargoyles in one encounter and in another 25 level lich (Example taken from [FONT=Book Antiqua, Times New Roman, Times]
Ex Keraptis Cum Amore, Dun 77)[/FONT]. While the later is definably harder then the former both present challenge due to limited resources. Due to their (more) limited number of spells, spell casters did spend some battle not using spells, in favor of saving them for “rainy days”. This come close to my image at the time of what a heroic adventure should look like, based on the books I had read.
Case 2: DM Fiat. That is, it is more acceptable for the DM to pick and choose which rules to use or change/make them to make the game experience more enjoyable for all participants. I realize that is more of a culture thing, but the latter editions very detail rule setup lulls me and most of the people I games with into a false sense that RAW should not be changed ever.
Case 3: Settings
I like fluff over crunch. Another helping of Plancescape, everyone?
Case 4. Combat and pacing
I like fast. short and brutal multiple encounters. I like being able to run a published adventure in once game secession (4-5 hours).
Due to the lower hp totals, the feeling of danger permeates combat. So PCs often look for way to avoid getting in unnecessary fights.
[I only run a party to 14 level, so I cannot comment on higher levels but in my experience
![Devious :] :]](http://www.enworld.org/forum/images/smilies/devious.png)
While magic-users eventually start to catch up to fighters in combat, thank to the easy spell failure, as illustrated in this example from drg 173:
“[...]
foes can disrupt spellcasting by throwing almost anything at the caster: small sacks or pouches with flour in them, light (nondamaging) pebbles, even mud pies. The act of dodging a blow, which occurs if a spell-caster wants to apply his armor class bonus from dexterity to prevent his being struck, negates his spell-casting.”
and higher level monsters having a) better saves b)things like [fixed percent] spell resistance c)resistances and immunities. Well a mage may out deal out quite a bit a damage a few times, but the warrior classes did not become obsolete at high levels.
While there are not as many abilities, items and options; due to slower advancement (DMG suggest 3-6 adventures per level, in my experience is 4 or 5) players tend to improvice more with what they have and worry less about advancements and builds.
Case 5: While high stats are always desirable it is possible to play PC with some weaknesses. In 2ed DMG there is a section about playing “hopeless” characters that is pc with scores below average (3rd tried to do something similar in an article “Wise As An Ox, Strong As An Owl” drg 284). Since ability scores have to be higher before starting to make a difference in play char with 8 and another with 12 in a non class requisite score were mechanically similar and it fell on the player to rp them differently. In 2ed I had seen fighters with str of 14 and/or wisdom of 8, not in 3rd or at least not for long (they died off). In 4th that would be even more suicidal by RAW. I am not saying one is a better system, just that they make different assumptions. I just like being able to play the stereotypes without being over penalized.(big dim-witted fighter, the old mage with a bad cough)
Game story: I had a player with STR16 Int15 Wis 8. The player deiced to play him as somebody who is fascinated with the epic stories, and has a bard's memory and facination for them. The thing is character also believes them to be the unabated truth and try to measure him to their standard. That led to some very amusing rp.
Onlooker:"You can punch trough a stone wall?!"
PC: "Nah, even less known hero Trudegen the Sly in the Epic of Hongar managed to kick in a storm giant's keep door as indicated in verse..."
Onlooker:"That is very nice, but he is not here. You are. And ... YOU CAN PUNCH THROUGH A STONE WALL!!!!"
Case 6: Magic items.
Those items are less accessible and thus more covered, while there a lot of burred treasures in lost tombs the PCs have to actually go there to find them, instead of scrolling to the "Magic Mart". Even making items is an (excuse for) adventure. Not every item can be easily duplicated or usable in combat. That to me keeps them feeling mystical. Again I realize that may not be every ones preferred cup of tea, but it happens to be mine.
Is the game perfect? No. Do I like the flavors of other editions? Yes.
2nd just happens to be the one which most closely matches my preferred style of gaming.