For the purposes of this specific forum post, I've personally found the following channels that have RP-centric discussions and interactions. If I have missed any, or you wish to promote a channel, please feel free to do so in a reply below, I may edit the original post at a later date to include them.

Full OOC Channels: STORP , STRP (as run by www.startrekonlineroleplayers.com)
IC/OOC Channels: Roleplayers , SubspaceRP , 10FWD
Full IC Channels: Alpha57012P

Common RP Locations: Earth Starbase Club 47 Lounge , Risa , Deep Space 9 Quark's Bar (Typically Instance #3)