I don't have that class however I can point you in the right direction initially. Have a look in the L2 Library sction (left) at the items and equipment, armor sets. There you can see that different abilities each have and what you can gain from having certain complete sets.
Tallum, Majestic, Nightmare, all are good for PvE
Going for PvP some say NIGHTMARE FTW
other say: with C5 NMs resist are so important!
some other say: OMG I need DC for PvP too much anchor/ls out there
to be really honest, just make your choice according to your playstyle.
a +Dex +Str SK will want to have a Majestic (even more PAtk and Stun Resi) a mild +Str SK will have fun with NM...
Others with +Dex will rely on Tallum for the attack speed...