I'm a high magic-fan. Doesn't have to be omnipresent...but magic should be available and usable to great effect...even if only through items.
That and/or psychic powers. But something should be usable for me outside of swords and arrows.
Technology, in general, is not a draw. "Modern day" isn't really a draw. I want fantasy and escapism.
But a dichotomy works. Long as the magic is there and understandable. Kitsune's suggestion of a mix of steampunk and high magic would interest me. But pitch me a straight "steampunk" with no magic or psionics (available for the players, I mean) and I'm likely to take a pass.
I can get down with pretty much anything terrain-wise, climate-wise, monsters/enemies-wise, races-wise. I'm apt to choose a fairly standard race for myself, but I'm not likely to turn down a setting based on available races unless you tell me what I
have to be. i.e. "All PCs in this campaign must be human...or dwarves or whatever" Don't like that much for a setting I'll be spending a lot of time in/on. For a one-shot or limited run "all halfling group", for example, is fine...but not if we're going to really work/explore a major campaign setting. I dunno...I'm a sucker for diversity, I guess.
An' I does likes me role-playing. So if it's going to be a straight combat-fest, then again, no thanks. One-shot...or the occasional "hack-n-slash" dungeon delve is good/nostalgic/fun from time to time. But for a prolonged campaign setting, I'm going to need/want some NPC interactions, political and/or international intrigue, mysteries, something to work my brain along with my sword-arm is definitely preferable.
And Details! Details! Details! Immerse me in the world. Engage my imagination that I don't see my character existing anywhere else.
Annnnd...eh...I guess that's it. It can be done a million different ways...but make sure there's magic.
--Steel Dragons