I played Vallon Zek and even a bit more into the Zek mergers.
It was originally <Defiant> and <Twelve Prophets>, but they petitioned for guild war unlock (removing the level restrictions for attacking other players with the other guilds tag) and <Defiant> removed <Twelve Prophets> from the server at that point.
There is an interesting story in Wired magazine about what <TP> was really about (
here).
After that, it Was <Ebon Dawn> and <Ancient Order> on <Defiant>'s heels. Luclin & PoP drove the server to X-teaming (mostly because the "Dark" guilds didn't have access to Bards) and <ED> & <AO> merged and became <Ancient Dawn>. Most of the purest (no X-teaming) guilds broke up and formed new guilds or merged into <Dark Defiant Warriors> or <Zephyros> which eventually just became the feeder guild to <Aduentus>. Few years before the merger, most the other guilds had moved to WoW and <Aduentus> all pretty much joined <Defiant>.
I loved VZ simply because the community self-regulated ... if you trained, corpse camped, OOC trash talked, immy healed, or any other general douchebaggery your chance of joining an end game raiding guild went to zero.