. +DEX : increase in crit rate for more Lineage 2 Adena damage.

. +STR : more damage is good damage.

SpellSigner
As a nuker, you want to level with +INT, you may add +WIT later for PvP. dark crystal robes for PvP, nightmare robes for PvE. get a sword of miracles in A grade with acumen, and/or a sword of Valhalla in B grade with acumen.

. +WIT : faster damage and more magic crits.

. +INT : more damage per spell.

. +MEN: more mp.

ElementalSummoner
By increasing your attack speed, you increase your cubic fire rate. Using a dagger  Lineage 2 Adena helps to do this. you may want to get a set of blue wolf light or doom light or robes to +6.

. +DEX : increased fire rate for cubics.

. +WIT : faster heals.

. +MEN : more MP.

ElvenElder
Note that you cannot change your INT stat. you may want to try to get an avadon robe set to +6. any weapon with acumen will do Lineage 2 Adena.

. +CON : increased survivability in PvE.

. +MEN : this is essential as you will run out of mp otherwise.

. +WIT : this is also essential, to increase % restored with "resurrection" and fast heals.

Destroyer
The destroyer is a master of weapons, if you don't have 3+ "situational" weapons in your warehouse or on your person, you simply aren't playing the class to its fullest. majestic heavy is good with +STR, doom heavy +6 works well with +CON. blue wolf heavy +6 would help you to catch up with slower targets in PvP.

Because you have no ranged attacks, its good to carry a bow, and though I don't know of any Lineage 2 Adena destroyers that do AOE parties (and I've asked most of the high levels on my server), people that have never played the class say they are awesome at it, in which case you may also want a polearm.

You should have a blunt for stunning, any blunt will do. an over-enchanted greatsword with the focus SA works better for PvE but a dragonslayer with the critical bleed SA works better in PvP.

. +STR : more damage.

. +CON : more HP for PvP, but get a health SA as well.

. +DEX : helps you catch enemies in PvP.

Tyrant
Tallum heavy and blood tornados with focus worked very well in C3. I have seen a lot more Lineage 2 Adena tyrants recently in light armors instead of heavy, especially nightmare light with dragon grinders, most likely with the health SA. it also doesn't hurt to have another set of fist weapons for PvP with some sort of risk SA on them, for when your hp drops below 30%.