This is an older build that I saw while observing GvG's awhile back, they're not as popular anymore, but they pack a good punch and they can generally keep the damage coming rather than having to wait for their combo to recharge.
Attributes
Dagger Mastery: 11+2+1
Critical Strikes 11+2
Shadow Arts: 8+1
Shadow Arts is for self survival, if you have a good monk consider dropping SA to increase your damage output.
Skills
Unsuspecting Strike
Wild Strike
Critical Strike
Twisting Fangs
" Coward! " [Elite]
Dash
Shadow Refuge
Ressurection Signet/Feigned Neutrality
Equipment
A Full set of Radiant ( + Energy ) armor.
2 Sets of Daggers: 1 Zealous, 1 Non Zealous.
Usage
Unsuspecting Strike and Wild Strike have recharges of 4 seconds, meaning you can alternate your dual attacks pretty quickly and effeciently.
Zealous Daggers and +3 Energy Crits should provide fountains of energy for you, compensating for the large energy cost of your lead attack.
Search for fresh targets, Ususpecting Strike will hit for 100+ damage on a target above 90% health.
GvG / AB ~ A/W Sustainable DPS Assassin
Llednar