I would cast my vote for /skyblock, cause I'm there most of the time now,
but i also enjoyed my time on /survival when i started on manacube.
I thought it would be fun to play on a server and just to make my life harder than it has to be, I did the tree-spirit-challenge... only to notice an hour into the game that visiting /spawn or other players (with protected land where u cant "greaf" by extending the roots of ur home-tree) ends the challenge unless u bend the rules xD well well...
At some point i might try /creative, cause i do enjoy me some w/e, but I'm not much of a beatuy-builder so that might not be for me.
Nice posts everyone <3