The Best Campaign youve ever played?

Okay so I like D&D Stories and hearing what other people liked usually gives me ideas to put into my game, granted that can end up with the 'We DM the games we want to play' but if everyone else in the group enjoys the gameplay then its a good time all round.
Anyway id like to know what were the best campaigns you've played in either content, memorable moments or anything about them really...

Ill start off:
One of the best campaigns that Ive played was a 'Drow' Campaign in which every PC was a drow and the DM read into the society values etc of drow culture to make everything a lot more immersive. In the group we had a female cleric who was some relation to the leader of a powerful house in the city, everyone else in the party became her bitch which made for interesting role play which shifted whenever there was a member of the main branch of the house around and the manipulative moody cleric went to grovelling and being almost charming, well as much as she could be. Sadly this campaign didnt go on long enough for the players to reach all of the goals that the DM wanted but throughout its brief time there were a lot of really good character interactions that added to the fun. The only problem with drow culture is you never know when they are going to stab each other in the back... some of the stunned faces at the table as two members of the party turned on another one for personal gain were priceless

I dm'd a campaign where an elder Blue dragon had made a bargain with the Far Realm, and was opening a mass Gate to allow the native atrocities to flood the Prime Material.
The group had to travel the world to gather specific materials they needed to make special weapons, all the while facing hordes of abominations.
It was almost elder evil-esque.
Really was a great time all around.

My favorite campaign I've played in (not ever, for I was DM for that, despite preferring to be a player), was set in a very small comparatively high magic country (Eberron style high magic, give or take). I was playing a whisper gnome shadowcraft mage who was very pragmatic-neutral and very patriotic. Due to natural hazards, this country was separated from the rest of the world, and common knowledge was there wasn't anything else on the world and this country was all the safe land that existed.

One of the players was a warforged, but the fluff was altered drastically. All warforged had been deactivated for eons of time and required special magic to get them to work again. This warforged was basically from a somewhat altered, modern, real life setting/time period in which a massive war broke out and both ruined everything and introduced magic to the world. Warforged were re-purposed criminal minds in robot bodies to be soldiers. My country had figured out how to wake one up, my character was a skilled magic user and patriotic militia gnome, so I was tasked with field testing it to see if it was a good idea to wake more of them up.

Discovering the rest of the world, finding hidden clues that this was a post apocalyptic setting in the vein of Adventure Time's Ooo before the show existed were awesome. The rise to power of our group and political influence we wielded (or ineffectually flailed around at times) helped the setting feel very alive. My capability to use Wizard spells to bypass challenges left and right in often humorous ways left my ego happy.

But one of the best parts was the banter between my character, who was field testing and researching this reactivated warforged, and the warforged, who made pop culture references and was, in my gnome's opinion, possibly non-criminally insane and very handy in combat. Some of the cultures encountered had aspects which my gnome wasn't familiar with but the warforged was, the best of these was the newspaper incident.

We got to a town that produced a newspaper, and my character wasn't aware of what that was, so the warforged explained it as "It's a thing that tells you everything going on in the town." My character misunderstood this to mean it was an extremely potent divination artifact that would allow you a fairly huge area of perception and understanding, so he had to have it. We spent probably 20 minutes of game time with me exploring the town to figure out how to convert my pure gold coinage into paper money so I could purchase a newspaper, and the entire table was laughing the whole way through.

In another city's library I used Scholar's Touch and came to the conclusion that the book The Picture of Dorian Gray was a historic work about a lich.

Sadly, the game died well before its conclusion after I sent all of the macguffins to a random location on the Positive Energy plane because I (and my country) were being betrayed and my gnome that was a reasonable response. The traitor had secretly stolen all of the macguffins via fiat, which the fiat I could've done without, but it was a great game despite it.

The best part of campaign I ever played was actually an adventure called the campaign of the wolf. It was back when 3.0 first came out. The DM made the mistake that CR 1 = challenge for 1 not 4 first level characters. It was against Druids(who never showed up in person) who summoned wolves, rough numbers it was 150 commoners with a few first level characters and a commander with a few levels. Against about 20 wolves with summons mixed in to round the number up to a nice fifty with druid animal companions. Needless to say the campaign was a complete route, three days and nights of trying to survive in barn's and farm houses and getting a tactical retreat out of the contested area. The NPC friends made in that adventure lasted the whole campaign which lasted to level 12ish. It really hit home the difference between an adventure and a normal person when it came time for the second adventure.

The best whole campaign was probably a campaign that ran across most of the published adventures in Eberron. Really opened up a lot of flavor to Eberron to the group as it was our first run in the world.