In all honesty, I am a member of over 50+ server on Discord and I am only active on Neoxian's Discord Server. The people are fun and active there and Neo also do some random giveaways to his Citizens, which makes it more fun compared to other servers since you have something to look forward too. I mean getting a full vote from a whale? Woah! XD
I also sometimes read some discussions on the SteemSpeak server. I do not chat though but the discussions are often times interesting there. Back when Steem was down for hours, that server was probably the first one to talk and explain what happened, why Steem was inaccessible for hours and why Steem users should not be worried.
Last but not the least P.A.L. Well mostly for their bot. Need I say more? XD