I like go much more than chess. I'm still a very big fan of chess, but it's just that I think go is an even better game. The only downside is that it is far less well-known than chess in the western world, leading to a smaller library of English-language literature on the game and less opportunities for play and discussion. However, the internet and dedicated go clubs of enthusiastic players help remedy the latter.
Go has wonderful deep large-scale strategy blended with localized tactics. A game of chess feels like a very complex, but solitary tactical battle in comparison. Localized fights in go can reach similar levels of tactical complexity, but then you also have to consider larger-scale strategic aims.
Go and chess are in the same class of games: two-player, sequential moves, perfect information, and hence limited to the incredibly deep actions on the board.
Diplomacy is also a beautiful game, but in a very different, incomparable way. Obvious differences are the simultaneous moves which give rise to imperfect information. More crucially, however, there is a complex 7-player dynamic, and, while the actions on the board are relatively simple, the true depth lies off the bound in the boundless realm of communication and relationships.