I like a lot of them but here is some i can think of:
Warlock:Mercurial dawn/Aaru's passage/babylon/Cryptographic
titan: Sulfur burnish/Cryptographic/thunderdevil
hunter:cryptographic/nebula glow
If only i could use Sulfur Burnish on my other two classes ;_;
Right now I have thunderdevil on my warlock, it gives a sweet patchwork look and texture to the barkhan dune set.
My hunter's shader changes based on my gear and cape, but I'm using bittersteel right now.
My titan, who is the scrub of the group, pretty much stays in banner colors (again, depending on his gear), as that is really the only time he gets to break orbit and leave his ship.
Of those, Goldspiral; it's the shader I use in Iron banner. My warschlock even wears it at other times.
My Titan prefers Walkabout, though. My Hunter Cleopatra AK.
Depends on the gear equipped and your mood. I like the old gaurd or one of the black ones from srl. Sometimes just something different from what I usually run. Then I play a match or a strike and usually just change back because I don't like it. Sometimes I run no shader.