[greatdane]

It depends a lot on the circumstances. If people have terrible gear, magician is one of the best classes. The pet can pretty much take on any melee class straight up until endgame gear, plus magician nukes are pretty decent when they land. Earth pet will permaroot anyone if the root sticks. Once people have proper gear, magician becomes shit since they're completely defenseless, have no real utility, and their spells are so resistable.

With absolute top end gear, warriors are nearly unstoppable. Disciplines allow them to nearly (or sometimes literally) one-shot many targets, and a warrior with 250 svm just can't be parked if the server uses era-relevant resist mechanics. Rogues are almost as beastly, but they rely on positioning and the environment can make that tricky, plus they can't tank other melees and pets like warriors can. Monks are a bit like warriors except they'll have a harder time getting über resists and can't do insane crit burst, but if you fight dirty, monk is king due to how easily you can train people. The pure melee classes are pretty terrible without that gear, though.

In outdoor zones, bards are theoretically unkillable. It usually takes a while for a bard to actually land a kill himself, but with resist/dispel songs and selo, you're just not gonna land any fast-casting root or snare on him. If you try to cast something painful, which usually takes like 6+ seconds, he'll just dart out of range before the cast finishes. A bard who knows what he's doing cannot be caught, cannot be CCed, cannot be escaped from unless you gate or run to guards, and he will dance in and out of spell range while applying chant dots or sending charmed mobs at you. It's an absurd class in PvP, but at least they lack the raw power to wreck people fast.

Shadowknight and necromancer are pretty solid regardless of the circumstances. Those two will always be popular because they aren't too hindered by high resists and have good PvP utility, so if you want a class that is well-rounded and doesn't run into situations like "can't beat that class" or "can't beat people with resist gear", go with one or the other depending on whether you like melee or caster. Druids are pretty decent as well and have amazing PvP utility (port, track, snare + root etc.) but it takes forever to kill anyone with good gear because you can pretty much just use Winged Death which will get pumiced.

Ranger, paladin and wizard are a bit tough to define. A well-geared ranger is actually reasonably solid in PvP due to huge tracking, snare and trueshot (in Velious, at least) but will have trouble killing well-geared players. Paladins are insanely tough to kill, but they do pitiful damage and you can basically just decide to wander away when you get tired of it. Great for duels where there has to be a winner, not so great if you want to actually go PKing. Plus resists render all their offensive magic worthless. People like to think that wizards are great in PvP because of lures, but they do very little damage per cast and a wizard is fucked if he can't snipe you from a wall or something. In group PvP where someone can protect the wizard and he can wear down that raid-geared warrior who's raping faces, it's a really good class. Not well-rounded enough to be a PvP #1 choice, though.

Clerics are for group PvP. You can't fucking kill a cleric, you might as well not try. If you're a melee, he'll invul and stroll away or gate. If you're a caster, you will run OOM before he dies. I had a level 57 cleric on VZ/TZ and level 60 casters would regularly jump me only to eventually give up and leave because I could just stand there and heal whatever they threw at me. It took a melee to kill me, and if there was a zone nearby or I could get a gate off, they couldn't finish me off. At 60 and with good gear, a cleric is just immortal and not worth fighting, but they're also harmless unless they have a partner to babysit.

Enchanters are insane until resist gear becomes prevalent, at which point they become buffers/debuffers for group PvP. You can't kill anything that has 200+ svm even if you tash it, but an echanter is invaluable in large-scale fighting. Crimson potions kinda screw enchanters over, but if they didn't exist, Rapture would be a retarded spell.

Shamans are a bit unique. They can be almost as hard to take down as a cleric and they can be ogre for bash immunity, so their survivability is huge. Their casts are slow and extremely expensive, though, because the class is made for PvE (they all are, but you know) and you can't exactly sit around and canni in the middle of a PvP fight. Poison dots hurt like hell and people tend to have low poison/disease resists, but you can make cure poison potions and lots of classes can cure with spells. Pretty sturdy 1v1 class and great support for group fights, but shamans don't really melt faces if you're prepared to fight them.

For the most well-rounded class in the Kunark/Velious era, I'd nominate necromancer. There are situations where another class would be stronger, but necros are so versatile and have so many options that they're never really at a disadvantage. They aren't countered too hard by high resists or dispels, they have really good survivability/sustainability for a caster class, they aren't hindered by having to kill stuff with melee, they have a very strong pet, they can feign off mobs and can get most anywhere to fuck with groups due to having feign death, invul and both types of invis... and hey, they also happen to be one of the best solo levelers and farmers which is a huge bonus on a PvP server. A level 60 raid-geared warrior (or rogue or monk, to a slightly lesser extent) is probably the ultimate king, but your anus will be in tatters by the time you get there.