I haven't had any paladins in the games I've played or DMed, for some odd reason, except for one or two way back when. Only one I remember was in Emiricol's Bandora campaign, but the paladin was basically the group's leader and all, so we were all kinda going along with him and behaving ourselves enough to avoid problems with him.
Me, I tend to make different or more expressly defined paladin codes, based on the paladin's religion or knightly order. For my Rhunaria campaign I have two or three short paladin codes defined, for different orders (IIRC I have the halfling paladin code, the dwarven paladin code, and the Rizan human paladin code kinda defined but not quite finished, and the Gilden paladin code kinda worked on).
Hrm...this is what I have on my computer right now for the first two. Two notes: dwarves in Rhunaria are based more on Romans than on Vikings; and Rhunarian halflings call themselves Keth, and other races just call them halflings because of their size.
Dwarven Paladins - Praetorian Sentinels
[sblock]Oath of the Archknight
This solemn oath I make, in service to the mighty and venerable Exarch of Ur-Dalechron,
To show obeisance to the Praetor and the Archon, to the Demiarch and Prelates,
To show courage in the face of danger, never cowardice, never weakness,
To show respect before my peers, to all those above and all those below me,
To show sincerity in my words and my deeds, never duplicity, never falsehood,
To show honor through my actions, my speech, my goals, and my lifepath,
To show mercy to those who ask it, never cruelty, never indifference,
To show duty towards the people of Ur-Dalechron and allies in need,
To show loyalty to my leaders and the Exarch above all else, never betrayal, never hesitation,
To show compliance with all written laws not held by those at war with Ur-Dalechron.[/sblock]
Halfling Paladins - Vale Protectors
[sblock]Covenant of the Keth Protectorate
To the great spirit Keth I voweth, that this covenant bindeth me until rebirth;
That I shalt serve the needs of all goodly Keth, in all things that others cannot do forthwith;
That I doth protect all peoples from evil deeds, without hesitation or reservation;
That I shalt offer healing and counsel to those whom needeth it, except those whom would abuse it;
That I doth keepeth the secrets of the Keth and guard them forevermore, for the sake of our people;
That I shalt converse only in truth and sincerity, fouling not mine speech with falsehoods or epithets;
That I doth dispense mercy to all those who ask it, justice to the unrepentant, and generosity to the needy;
That I shalt liveth by and uphold the laws of the Keth and no others, abiding no foreign mandate;
That I doth live to protect and serve others, never to throweth my life away without just cause.[/sblock]