Wrote this back in may, not much has changed but I have yet to update it with levels. Feel free to reply with useful abilities that I missed. This is incomplete but may still be useful:

Abilities: For abilities, the following criteria need be met for an ability to be mastered: 1) The ability is masterable (if it is not, it will say so in the description of the ability on your character screen). 2) You must reach twice the level at which the ability is learned in order for it to be mastered. For instance: Multicast is learned at level 18 mage. Multicast is masterable. Therefore, achieving 36 in Mage will master multicast and you will then be able to use multicast as an alternate class. I can?t offer a full library of abilities, but here?s some helpful information about masterable abilities that are desired. I will list what I can remember, which should be the good ones. I will boldface anything that I think is so desirable that one could justify having the class taken exclusively for that ability. I will also boldface something if it?s semi-useful but learned at a very low level. Warrior, Reaver, Paladin, Berserker[/b] Multistrike[/b] Cleave[/b] Critical Strike[/b] Melee Flurry[/b] Power Style (?) Warrior[/b] Whirlwind Attack (Area melee attack)[/b] [/b] Berserker[/b] Battle Hardened (passive, adds to armor and health). L44? [/b] Ranger[/b] Fleet of Foot (passive speed buff) L76 Mage:[/b] Multicast[/b] (L36) (Self explanatory) Fusion Burn (?) (Reduction of mobs flame defense) Engulf (?) (Flame DoT) Druid:[/b] Forest Mist Petrify[/b] (L12?) (Melee attack with 3 sec stun) Nature?s Fury[/b](L16?) (Aura boosting melee damage to 112%) [/b] Chaos Warrior[/b] Unbridled Energy (L40) (Increase attack speed and melee damage) Sorcerer[/b] Spellbind (Mez) Wizard[/b] Dynamic Pulse Stunner Energy Burst [/b] Battlemage[/b] Energy Sabre (L80) (Melee AoE) Cleric[/b] Dispirit Foe[/b] (Reduced attack speed for Mob) L18 Dispirit Foes (See above) L96 Gleaming Shield Magic Crush Conjurer[/b] Phoenix Rising[/b] (Flame AoE) Infix Fury (Increase Melee Damage) Ice Barrier (Melee ward?) Multicast 2[/b] (4x spell cast) Spiritist[/b] [/b] Spirit Walk[/b] (Negates the next attack) Syphon (single target Leech) Area Syphon[/b] (Area Leech) Stinger (Melee DoT) Guardian[/b] Stone Hammer (Melee Attack on it?s own timer) Guardians Force[/b] (+3 damage, delay adjusted, lasts indefinitely) Morning Dew (HoT with magic evasion to boot) Some passive goodies that I forgot about? Quake Attack [/b](Melee AoE). Shaman[/b] Ruin (DoT) Decay (DoT) Steal Strength Steal Dex Expulse Corrosive Rain Curse of Enfeeblement. Healer[/b] Instant Heal Group Instant Heal[/b] Life Giver 2[/b] (Passive Heal boost) Illustrious Stand [/b] [/b] Monk[/b] Foresight [/b](L12? 20sec buff that allows evasion of the next special attack). The above is off the top of my head, but should serve as a general idea of who gets what, and what some of the big ones are.