Im really stuck as to the right fitting class for me. I have a 64 Warlock, 50 Rogue, 46 holy pally, 40 shadow priest and 26 druid.

I keep getting bored of a class and doing research on others, but i go back to my warlock because of the 353 Enchanting and 335 Tailoring. Anyways, here is some info to determine the choice:

Ive played Final Fantasy XI for 3 years:
was a main Ninja, Samurai, Monk and my first job was Red mage.

I like jobs of a low populated player base, and jobs that appeal to me are usually the rarest to find, the most needed in situations and whatnot. I also love being the support class. In  FFXI Bard and Red Mage were probably my 2 jobs i was the best at, and both were in very high demand. Im leaning toward priests, but they look like they get owned in PVP...

Recently, ive discovered the joys of PVP in BGs and such, i want a class that is good in PVP and well wanted in PVE for raids endgame content in general. Any help would be greatly appreciated.

I forgot to mention, i am Alliance side

Well, a Warlock in high-end PvE is very boring. So if you plan to do that,

Shadowbolt Shadowbolt Shadowbolt Shadowbolt Shadowbolt Shadowbolt Shadowbolt Shadowbolt
But all the classes have some role (maybe a niche one, but nevertheless a role) in both PvE and PvE.

Yea, you spam Shadowbolt but hey, big numbers can be nice! =D Any other suggestions? I loved it in FFXI when i was on my Bard and i joined a party to have the other members say "Oh sweet! we got a bard!" Or something to that extent. Can anyone relate to that?

Well, im not much of an expert, but i play MMORPG's all the time, mainly WoW :)

I would say, play a priest because, on most servers, priests are pretty scarce, due to hating the job to heal. I have a lvl 45 priest, and i hate it when i heal the best i can and because i cant effectively heal 4 different people at the same time, it's all my fault that everyone takes the aggro and dies.

Now, PvP, all the classes are relatively balanced, but still people shout out that 19/29 Rogues are too tough, and lvl 70 locks are OP. Who cares, in my opinion Shadow Priests can hold their own, and although people say "You should have rolled a Rogue/Hunter/Warlock" they will be the ones crying when they see that no heals are coming their way.

So, id say stick to shadow up to 70, then respec to Holy. If you have problems that you feel you are doing wrong (Using the wrong heals, wrong enchants etc) then either ask the Thottbot community, the Official WoW Forums are a great place too, and if not, ask a few lvl 70s on your server, because they know what they are doing.

Nzambi on Arathor(EU)

Think about whether you like randomness. Ret Pallies, Enh Shammies, maybe Arms Warriors all depend on the RNG (that's Random Number Generator for you).

It's all fine and dandy when it (say windfury) procs a lot, but sucks when it doesn't.

Sucks to spend the whole battle praying for a proc...

mage ftw!
pve quite good
and pvp damn good especially against warriors and rogues!
the trouble is with shamans :(