02 Apr 2009 at 04:08 - 15
There's more than one "most effective class" since there's more than one thing your party needs someone to be effective at.
A quick overview:
Damage:
For a totally structured team, an AP-MoP Necro paired with a OoU MM Necro and a HB-WW Warrior and supported by a Necro buff-bitch and other physicals plus casters with spears is about as good as it gets.
For standalone damage output, AP-AE-CoP Mesmer is probably the strongest.
MS-DB sin falls in the middle with reasonably high damage on their own, plus the ability to work well with a AP-MoP.
Damage Prevention:
Anything that spams SY! is nice -- Imbagon, "Godmode" Dragonslasher, MS-DB Sin (again), HB-WW Warrior (again), Incendiary/SY! Ranger, etc.
The PS/SB spam limited only by cast/recharge time on a E.Renewal "healer" is unparalleled enchant-based damage prevention.
For condition-based shutdown, Mandragor-In-Can Me/E is the strongest.
Healing:
Infuse on an E.Renewal "healer" (again).
Interruption:
Daze. Often earns a spot on the team for a Ranger that they otherwise don't deserve.
Knockdown. Warriors win here: Stonefist insignia and Earthshaker for hammer builds and Brawling Headbutt for sword builds.
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Recap:
As you can see, most of the classes can do something worth doing and be "the best they are at what they do."
The classes that are left out are Monk (totally outclassed by ele), Ritualist (worthless caster primary), and Dervish (outclassed by Warrior and Sin, shut out from best intra-team damage synergies b/c of AoHM's most unfortunate damage-type conversion).
Also, some "most effective" classes have more room for flexibility than others. Necro and Warrior have at least 3 top-tier builds each, and those builds have room for flexibility within them; while Paragons are stuck with Imbagon, and Imbagon allows basically zero variants that aren't strictly inferior to the "classical" build. The others fall somewhere in the middle.