CoP is optional, i dont think theres any part that ppl really exp off unless its Bibiki Bay at the high 60s.

There are many jobs..depends on what you wanna do really. I am bored so ima just list some jobs and my take..feel free to say anything about em, but in the end its up to you, tank, deal dmg, support, solo, or heal.

Tanks:

WAR-Expensive if you wanna be best, good versitility melee-wise, can tank and damage deal(DD), good variety of subjobs(MNK, THF, NIN-post 24, SAM-post 60). WAR/NIN with Utsu at lvl 51, CAN be the BEST tank out there. Dealing damage and using shadows. But only with a BRD and Carnage Elegy. Contary to what people say, they do NOT do crap damage and are mediocore. They can definetly hold their own.

PLD-Reletively cheap really, one of THE cheapest jobs. You have magic to keep hate, and a fair ammount of abilities to keep it steady when it goes rough. Most reliable tank, tho you could die easily vs ultra hard hitting mobs and have sucky attack not to mention limited sub job choice(WAR only).

NIN-Very expensive job, Shihei is required as well as enfeebles to keep hate. Not good at keeping hate back once it goes astray without Provoke. But is invulnerable to many attacks because of Utsusemi. Great vs ultra hard hitters. You can chain so many monsters because you barely need to heal! But it comes with the ninjutsu price.

Damage:
MNK-Expensive yet again if you want l33t gear, but as you go higher, you actually dont NEED pimp gear if you want to do good. I have seen parser logs between two MNKs, one with top of the line, and one with decent gear, and the decent MNK sorta sometimes beat the top of the line one. Good vs bones and GREAT DoT(damage over time), bad thing is no invites at certain stages, shines end game.

THF-Weak normal attacks, but great burst damage and hate controllers. Also good Skillchain closers with Sneak Attack Fast Blade pre 33, and Sneak Attack Viper Bite post 33. If you wanna do Distortion this is your job choice. Can pick coffers at higher lvls and has great soloability. Hell however is lvl 1-15 LFG =/.

DRK-Slow swings, horrible accuracy compared to most damagers(make it up with some gear), but great per swing damage. Great skillchain closers and has good Absorb spells and Dark magic. Problem with their great damage is that it gets em killed, so most sub THF post 60. Also there seems to be a surplus of em in most servers for some reason. So hard to get invites.

SAM-Skillchain masters, while they do good damage at lower lvls, they pale in comparision at higher lvls compared to most other damagers. Their power comes in Meditate where they can get a form of TP regen-ish thing, and be able to do multiple skillchains per fight and therefore gaining culmulative damage from skillchains. Their GKatana also gains more TP than any other weapon, and they also have a big variety of weapon skills with lots to chain from. Subbing RNG and having a capped Archery also makes em pseudo RNGs, not bad for dmg. Rumors of them having horrible accuracy, not sure about this, i havent seen that happening yet.

RNG-King of damage, can gain tons of TP per shot and swings of daggers and do SICK damage on mobs, arugably the best damager. However it comes with price of...well gil. Needs lots of arrows and every shot is gil from your wallet. Subbing NIN is also recommended due to RNGs stealing hate easily, so Utsusemi is recommended to give your tank a precious few more seconds to get hate back. RNGs also have low defense x-x owwwie. Gear is also important unless you wanna miss all your arrows(and gil).

DRG-Great Distortion openers, and almost every polearm skill has Impaction on them. Their wyvern is however NEEDED if you want to gain the edge on other damagers. They are a great damager til the 66ish where their Wheeling Thrust WS puts them a bit behind. Sucks at HNMing, but great solid damager vs flying monsters. People say DRGs suck, but in actuallilty, they arent THAT horrible as most ppl claim them to be.

Mage:

WHM-Best healers, gain those spells faster than a RDM and has status cures, group buffs, higher level Regen's and Raise's, not to mention Teleport. CureV does not have a limit cap so it can only heal more and more. Great Haste machines as well.

RDM-Jack of all mage traits. They can main heal pretty well if they concentrate on it, can magic burst pretty decently(only their lvl of their magic is learned slows their power here), best enfeeblers, a Refresher(MP Regen) job, and average sword skill. Can solo pretty well with the right subjobs and spells/equips.

BLM-Best artilery. They gain upper lvl atk magic the fastest, their magic bursts are just killer if unresisted. However that also got a few BLMs dead if they dont know how to manage hate or control it >_>;;;; Overnuking=bad ><. Can Warp and WarpII others. Expensive spells tho ><

BRD-Best support. Their buffs are without question one of THE best. They can sleep undead, buff atk/acc/def/eva/refresh/countless things...etc, and all without MP. FAST invites. Reletively cheap if you dont get the best things. However so far they are the WORST soloers..

SMN-Sorta another jack of all mage jobs. You need all avatars(at least all without Fenrir) to be good, you can heal decently, attack decently with avatar blood pact(MB and SC too), not to mention have a unique set of buffs just for yourself. However low HP is a problem, and sometimes ppl will stick you to be main healer instead of a summoner(more happens in low lvls than high).

Solo:

BST-So far BST are best at soloing. Not that they suck at partying but best suited to soloing. They can charm mobs around them and sic em on other mobs, and gain exp that way. Best to fight suicidal mobs for exp of course. However if you dont PT with other BSTs, you are ALONE, and if you die you are screwed right there. Its risky because no one watches your back but yourself most of the time, and it can get lonely. But if you wanna solo here ya go :P

There i am less bored now...*does other stuff* O.o