I only play my Warlock now, and I'm pretty much 50/50 on Sunbracers and Chromatic Fire.
Sunbracers are very flexible with weapons, and I mainly use Conditional Finality, Hollow Denial (Lead From Gold + Killing Tally), and The Other Half for well skating.
For Chromatic Fire, I just use Wish Ender and arc. Wish Ender is already insanely powerful, and the added blinding explosions are just so good. I usually pair it with Forbearance or Techeun Force (Rewind Rounds + Controlled Burst), and Apex Predator (Reconstruction + Bait and Switch).
Warlock - I'm mostly addicted to Osmiomancy Gloves. This build is even better after the buffs/fixes to Coldsnap Grenades and Iceflare Bolts.
Titan - hard to beat a good Sunbreaker build. I've been alternating between Synthos (which I find more personally useful) and Phoenix Cradle (when I want to be a better teammate). Honorable mention for Sentinel with Bastion because everybody loves overshields, but I haven't finalized a build yet.
Hunter - Gyrfalcon with Telesto makes a better combo than most people realize. Because of the charge time and the delayed detonation from Telesto, volatile rounds are extremely easy to keep up.