Anyway, it should be obvious from the above that pre-written settings are even more valuable for me than the average GM. Yes, I like to create my own settings, but rather like a drug addict, I should not necessarily be given what I like.
So what do I like in a published setting? I’m a fan of “dark”, be it dark fantasy, dark futures, horror – you name it. You can probably deduce my favourite settings from that straight away. The Warhammer 40k universe, Dark Sun, Call of Cthulhu, all big favourites of mine. But at the root of this, I’m looking for a setting that inspires me. For some reason I find darkness inspiring, go figure. But it isn’t the only thing I like; one of my favourite settings is Immortal: The Invisible War, which is more baroque than dark. Whatever the setting, I’m looking for something that’s going to trigger a torrent of ideas.
I pretty much never use published settings as is, though. This is a point of pride. I feel the need to put my own spin on it – often ironing out annoying inconsistencies in the background (and then reintroducing them through misinformation and rumour), and adding in major historical events that I can tie into my plots. Call me a snob, but I regard any GM who doesn’t introduce their own ideas into the game world as not really trying, even if this does slightly defeat the purpose of a published setting.
Bottom line: published settings are an incredibly useful shortcut to enable the GM to skip world creation and focus on what really matters. But I imagine I’m not alone in thinking that this also means skipping a big part of the fun of being GM.