The game has a quest line that levels you to 60 and beyond. My first character is a Trickster Rogue I got to 60. The character is pretty much maxed out, but that is from making a bunch doing auction house tycoon. Not from dungeon running. Right now, at 60 the dailies and stuff for 60 aren't in the game until the 20th "live release" patch. So once you hit 60 the only things to do are pvp, foundry, and dungeon runs really. Pvp is a bit annoying due to all the people that just AFK through them. Which means if the other team has afkers you faceroll them. If your team has them then you get facerolled. Also level 60 pvp is about who can 2 shot whom faster.
Foundry is cool, but there is no real reward for doing them except out of a sense of saying you did them. If you like doing stories other people made up, then foundry is cool enough. Still I find much of that content a bit boring.
Which leaves dungeons to do. Unless you have a static group of friends or you are a cleric... you aren't getting into dungeons right now. The server population is like 90% TRs and 10% everything else it seems. What's more annoying is how unbalanced classes are for PVE. They are really balanced for PVP surprisingly, but are horribly balanced for PVE. Most of that has to do with how NPC boss mechanics and threat generation right now work for PVE.
So basically dungeon groups consist of 1 defensively built, with some good offense, Trickster Rogue. 2 Control Wizards, and 2 Devoted Clerics. That is except for the cheese groups that use certain exploits of the guardian fighter class. That class has had several infinite damage exploits available to it since the game started. Baring the GF exploits, they pretty much suck in most groups. A good Trickster Rogue will out tank the tanks easily enough. You only need the TR for boss tanking.
Control Wizards are fine, but again there are a lot of them. 90% of the pop seems to be TR's while 9.9% of the rest is CW's. The remaining 0.1% is the other 3 classes from what I can see.
Which means if you want to be in dungeon groups and not immediately kicked out of a random pug, you better be a cleric.
Which is why I'm rolling a cleric right now. Oh, and clerics in this game are not like clerics in other games. It is not "whack-a-mole" with the health bars style of healer playing. Clerics do damage abilities that happen to also heal the party members. If you are looking to be a sit on your ass healer, this is not the game for you. You'll instead be moving and kiting a lot. You'll be needing to keep up a constant stream of dps because that is what heals the party. As well as placing Astral Shield down as needed.
So if you are starting NW right now, I'd highly recommend playing the cleric as your main class. If you like DPS, always getting into groups, and feeling like the most important person in the party then the cleric is where it is at.
Oh, and if you want to be a control wizard, build yourself for Arcane Singularity spam. That's really the best build that is far above anything else. You want to be able to use Arcane Singularity every 8 seconds or so. If you can manage that, you'll make dungeon runs for the group a breeze. Especially with 2 CW's with that build who stagger their Singularities. Most of the adds never get to even attack the group with that setup.
Another thing, if you are leveling up and want an easy time of it always grab the devoted cleric companion. The only exception is if you are a devoted cleric class. Then grab the man at arms companion. Once you hit 60 the only companion you'll look to try to acquire is a cat or ioun stone. This is because at level 60 in dungeons companions just die instantly regardless of the type. The cat and stone can't be targeted as they are not combat companions. Thus they can't die. They just act as stat boosters for your character. The only other companion that can "hang" around without dying is Galeb Dhur. It's the only purple tank companion available in the game from the Zen shop at 3000 Zen. Which is $30. What makes Galeb good enough to use in high level dungeons despite being a combat pet? He doesn't die easy. He has a self heal for 8% of his max health every 10 seconds. That and a massive regen stat. He has a ton of defense and health. He doesn't go down very easy even in level 60 dungeons. Every other pet isn't worth the time to level them up right now.