I have been genning mostly medium worlds (my system can't quite cut it but histories under 150 years, keeping it 4x4 and habitually abandoning forts before the third year helps.) I have found 50-60 civs (with all masterwork, fortress defense and cavern races active) to generate relatively few civ-placement rejections, and gives a civ of every type with many dupes.
I turn evil clouds way down, to 2-3. I would turn them off, but, well, I do want them to exist, I just want it to be notable if one finds me, and for it not to happen every game.
I do at least 10 levels above the first cavern if I'm dwarfing because I want to put my bedrooms below the noise of the tree chopping. My one human round I actually tried to put everyone at the top of a tower to evade the noise. People were sleeping on the ground by the third season and I realized what a fool I'd been.
I also usually turn my embarkers up from 7 to 13 (preferring Tolkien to Disney), and accordingly increase embark points to 2500, because I am a cheater.
Edit: I do play with all the FPS-boosting simplifications off (daughter of a carpenter, friend of a geologist, so the extra stuff does add richness for me.)