Lord of the Rings Online: Class Guide
From Captain to Minstrel, every LOTRO class explained.
Hunter (11 per cent)
The hunter, like the Loremaster, is a perfectly, averagely popular class - exactly 1 out of every 9 of the Turbine guys favour it. It's the ranged damage class - the "nuker" in MMO parlance - able to do more damage to a single target per hit than any other class, and without them fighting back. It's also the class for yellow-bellied cowards and hence is favoured by Elves like Legolas, though humans can also excel at it.
Hunters die easily and can't heal (save poisons), so have to be careful not to build aggro in parties, which is tricky considering their massive array of weapons, projectiles and high-damage. As with WOW, hunters can track any type of creatures except dragons (and if you can't spot them, you shouldn't be playing) and deploy traps, but unlike WOW they don't have pets (the Loremaster does) and can't mark targets (look to the Captain). Hunters can also teleport their compadres to a range of locations, as well as to any of the campsites which they can set up, which means they're good to have along for long instance chains. (Campsites are useful fixed locations that provide morale and power regeneration when out of combat.) They can also run super-quick, which is good for power-levellers, or running away...
Loremaster (11 per cent)
These wannabe-wizards are also exactly, averagely popular with the developers. Elves make the best hedge-wizards, but humans can manage it too. Their skills are all focused on crowd control and, because they're rather squishy, they have a couple of pets they can call upon to distract their enemies - bears (only useful as weak off-tanks) or ravens (excellent at distracting any enemy). They can mesmerise two enemies at a time, root others to the spot (like the Hunter's trap) and do reasonable damage themselves up close (though that's not always wise, as damage slows their powers down).
Because of their variety of debuffs and their pet, Loremasters make great solo avatars. However, their healing and power-replenishment skills are very weak, with slow timers, and actually are transfers of power or morale from the Loremaster, leaving him dangerously weak. Moreover, their skillset is focussed towards very slowly killing enemies one by one, so they clash a little with over-aggressive champions and their disruptive area attacks.
Guardian (14 per cent)
The third most popular class at Turbine, Guardians are the game's main tanks, able to absorb damage and draw enemies to them. They can only really cause damage when they're being attacked up close over a long period of time (though they have a selection of area-effect attacks), so ranged and self-healing enemies are their nemeses.
Because of this, solo-play with a Guardian is much slower, so it's worth staying teamed up all the time - something that's true throughout the game for all classes, especially if you're seeking to achieve the deeds that unlock the traits and skills that are key to successful, flexible higher-level play. It can also be quite expensive being a guardian, due to the tremendous amounts of repairs you have to make - but a kind kinship will help you out there.
The Guardian should be leading any exploration of instances (except, perhaps, for a scouting Burglar), and is best deployed in front of the fragile healers and nukers, but close enough that he can turn and reclaim aggro from them without moving too much. Attack slowly around a Guardian and let him attack first, so that he can build up and retain aggro - it's a lot more difficult to take enemies away from someone else than it is to attract and hold them in the first place. Dwarves are the preeminent Guardians, but humans can also tank perfectly well - think of Gimli or Boromir, if you need an example.