Going into 2009, this is still the best PvP game ever made by a long shot.
The central conflict in DAoC is the war going on between Albion (the kingdom of King Arthur), Midgard (Norse/Viking lore), and Hibernia (Celtic/Elvish lore). Unlike many newer games, DAoC is not designed around the EQ/WoW framework, and does not seem to share the Tolkien influance which seems almost omnipreasant in the fantasy genre.
Upon starting, players will have the choice of playing one of the three realms which I named, each realm bearing a hugely differant feeling and having an assortment of unique races and classes, which will then be personalized further once the player levels up and picks the spec line which he is interested in.
The games PvE content is free form, rather than quest based. There are task dungeons and kill tasks which will provide some level of quest based experiance, however the majority of the time you spend leveling will be grouping other players and finding new challenges and monsters to kill for loot and experiance.
The best part of this game is the PvP, which is called a RvR (realm vs realm) system in daoc. While you may never attack someone from your own realm outside of a dual, the pvp system that daoc boasts strongly directs you to group with other members of your realm in order to attack enemy keeps and castles. However solo play is also very viable for the daring and skilled cyber tactician, yielding increased realm and bounty rewards for thoes who are able to sucessfully attack and destroy enemy players without the aid of allies. As mentioned, realm points and rank are the key rewards to engaging in RvR play. Realm points are points that you get for competeing in RvR play, and can be spent on new skills, or passive abilities which increase the power of your character.
In daoc, the endgame is pure, glorious battle in so many forms. If the epic pve encounters are not enough to satisfy you, the pvp will be.
Assuming that it maintains a player base, daoc will continue to rule the MMO pvp scene untill the day mythic pulls the plug on the servers.