The absolute best experience I've had with this was a 3.0 D&D game that ran for about 2-3 years, on and off. Its also my longest running campaign that never got rebooted, reset, or suffered form character rollover.
The principle characters included:
- Morgriffia, a human Paladin of Pelor. She is the stern Paladin of sternness. And she'll cave if your skull with a warhammer if you give her any guff. She really wasn't as bloodthirsty as I make it should, nor as prick-ish, but she somehow developed a reputation because of her frequent use of Detect Evil. She was that close to being able to get a griffin as her mount when the campaign finally petered out.
- Nathanial, a Lawful Neutral human Wizard/Monk. This character had straight 14's, except for his Charisma of 10. The player decided he'd play the character as a total dick, which, compared to the other two Charisma-mongers in the group, he was. As an added point of tension, Nathanial was a "Gray" Necromancer, a wizard that studied the conditions of death and negative energy for the sake of knowledge, rather than raising armies of undead. Needless to say, he was often at odds with the Paladin
- Rolf, a Chaotic Good Cleric/Barbarian of Kord. He had the best stats ever (14's through 18's), except for his Intelligence, which was slightly below average. We decided he was chosen by Kord because Rolf reminded the god of him, when he was younger. (We played up the idea that Kord was this good-nature "great big jock" that somehow achieved god status.
Along the way, they encountered a number of shorter term PCs (who came and went for various reasons). There was a wannabe Paladin who idolized Morgriffia and lept blindly into danger. A halfling warrior (thief/ranger) who has a venomous hatred of the undead. A "dragon hunter" con man who ended up getting in over his head. And so on.
Their one long-term NPC companion was a young Neutral Good bard. Bards, by the way, make a fantastic mouthpiece for the GM to give the players some clues, input, or whatever.
Durable magic items were exceedingly rare and potions pretty uncommon, but alchemical items were very, very common. By 8th level, I think each character had one permanent magic item.
The framework of the plot was:
The world has been (mostly) free from monsters for almost five hundred years, thanks in large part to the efforts of a group of powerful wizards that created several magical seals to keep evil at bay. A human empire has risen and spread across the land. The world had a strong leaning toward Good and Law (though not necessarily Lawful Good). There were communities of dwarfs, gnomes, elves, and halflings. Halflings were the most common and actively interacted with humans and lived in their communities. The others, not so much.
There were still evil-aligned communities in the world. Orcs, goblins, kobolds, and other existed, but has been pushed out beyond the fringes. Occasionally they would rally and try to attack the human kingdoms, but they never stood a chance.
A wizard named Margrave came on the scene. His family was old, powerful, and wealthy. He was thoroughly corrupt; Evil to the core. He killed his family and spent their fortune to attend one of the wizard colleges. He was expelled for conducting "unsavory experiments," but by then had stolen hundreds of maps and documents from the college's libraries. He spent years traveling from site to site, trying to unearth lore that should have stayed lost. Ultimately, Margrave began undoing the magical seals that were keeping the monsters (demons, devils, dragons, and so on) from entering the world, with the intent of usurping a certain demon lord and using its power to become a god.
After all that, the campaign began. Rumors were flying about monsters coming back to the world. Communities at the fringes of the empire being destroyed. The orcs and goblins rising up again. And so on. The empire was in chaos. Five hundred years of relative peace had softened empire's warriors, except for a few dedicated military orders.
The PCs forged a bond after traveling with a caravan and fighting off a bunch of ratmen. After that, I pretty much let the players go explore. I fed them leads and let them decide whether or not to pursue them. Toward the end, I made the mistake of feeding them a red herring and, unfortunately, they latched on to it and wouldn't let go. They veered sharply away from the final encounter and, try as I might, I couldn't get them back on track.
If you're still reading, my suggestion is to keep the red herrings to a minimum, especially the tempting ones. Or don't use them at all. Give yourself a reoccurring NPC to act as a mouthpiece. If you feed them multiple plots, have the plots at least vaguely sketched out ahead of time (unless you're really good at winging it).
-paws