Thanks for the responses, good to hear different opinions.
Virtually all of my games have been PPSC so far - I think it will be interesting to switch to playing mostly WTA to see how that changes strategy, outcomes, etc. - and I like the fact that that's more like the original board game.
Playing anonymously (vs not) is an interesting one. In one respect I like playing against the same people repeatedly, and learning their strategies/abilities/preferences can be an advantage or a disadvantage, but is always interesting. And I've certainly annoyed a few people that I've played with by stabbing them, though I'm still not sure whether to feel guilty or not. Then again, playing anonymously can be quite a different challenge, having no idea who you're playing with, or their relative skills/motivations.
As for gunboat, I like the different type of challenge that it offers, but for me it significantly reduces the enjoyment of the game, as it takes out one of the key elements. I think all the elements of communication, psychology, persuasion, coercion, fooling, bluff, collaboration, etc., etc. are what marks this game out as unique compared to virtually anything else I've played. So to play without that - for me - really diminishes the quality of the game. (Although I do understand that it's a good way to hone your skills in tactical thinking.)
Live games - I've only played two, and been defeated badly in both, so clearly in need of some work there. Unless, of course, my opponents were cheating, which seems to be an accusation often levelled at people (in live games in particular?).
And in terms of the ethics of game-playing - I absolutely agree with above posters - I'll try never to NMR, CD, etc. and will always fight to the bitter end.