Shadows are good for Stealth attacks & Burst DPS. They can't sustain high damage during long fights however.
Best DPS glowstick wielders are the Jedi Sentinal or Sith Marauder. Both classes use dual sabers and have tons of damage dealing saber skills.
As with every class, it's all according to what fits YOUR play style best. Luckily we have 8 slots per server to try them all out!
*EDIT*
In game tech terms :
Jedi Consulars & Sith Inquisitors use Force Power for their attacks and heals. The Force Power meter starts full and drains down with each special used. Once the meter reaches 0 you become limited to using your auto-attack until you build back up Force Power to use another series of specials (hence the "Burst DPS" for Shadow or Assassin). - I have very limited experience with Shadow or Assassin, so others may be able to add to this.
Sith Warrior & Jedi Knight use Rage or Focus. Rage/Focus meter starts at 0, but when initiating the attack via Force Leap or using either the auto-attack + a couple of other saber attacks, they build Rage/Focus while attacking. This allows the Marauder or Sentinal to sustain DPS during the fight. They also have a few different Lightsaber Forms to use (defense / damage / balanced), along with a few skill buffs which can be used during combat with built up Rage or Focus points that can benefit themselves and their group or companions.
-- Edited by Menis on Saturday 26th of May 2012 08:04:08 AM