There's always lots of talk about how amazing such and such mod is, or how cool it would be if we assigned all dwarves boiling points of 0, but let's get our noses out of the raws for a minute to appreciate how incredible the DF stock world really is.
Now, there's about a million things I could write here, but for now, let's focus on the major races of DF: the elves, the humans, the goblins, and the dwarves. (I'm excluding kobolds for now because I can't think of anything interesting to say about them)
First, let's consider the world itself. When it was created someone or something sealed a whole bunch of demons inside pits and then covered the pits with adamantine and then covered the adamantine with mountains. Who could have done this? Dwarf and human gods don't actually exist in and of themselves, elves don't believe in gods, and goblins worship the aforementioned demons. The only actual [POWERS] in existence that would be capable of sealing the fiends of hell underneath the mountains are the demons themselves. So personally I've taken to believing that the demons we see ruling the goblins are the strongest demons, who imprisoned their brethren underneath the mountains so they wouldn't have to share the overworld. Discuss.
My next thoughts are about the elves, who are one of the most fleshed out races in the world in terms of development plans. Most players dislike the elves, as they should, since from a dwarven perspective they are insane hippy pansies that live in forests and actively seek to hinder industrial development. However, I'd like to keep talks of drowning the elves in magma out of this thread, since my goal is to better understand the elves as a player and appreciator of Dwarf Fortress, and not as the spokesperson for the dwarves themselves (in other words an OOC discussion not an IC one). That said, the elves are an enigma to me. I see that they value preservation of the natural landscape more than anything else, but it is a mystery to me how they can exhibit such serenity one moment and such savagery the next. What do you guys think? How do the elves see themselves? How do they see the other races?
My favorite race would probably have to be the goblins. I think I've got them mostly figured out. Think about them for a moment. They are the most technologically advanced race above the ground, building massive towers that make the human castles look like run down shacks. They live forever. They actually worship something that exists in a tangible sense, and don't waste time shouting words at the sky like humans and dwarves. They obviously believe that they are vastly superior to the other races, but they also believe that other races can be shown the light and converted to their superior society. This is evidenced by the fact that the child snatchers consider themselves to be the "liberators" of children. Now their [ETHICS] seem to suggest that they've adopted something that could only be called Social Darwinism. The strongest goblins rise to the top and the weakest rot at the bottom. The Demon is always at the top, and I'm not sure what role he plays in the direct control of the civilization, but that's still a point to ponder. In short, the goblins view themselves as the noble immortals of the world, watching over it from their stone palaces, and seeking to redeem the lesser races from their own inferiority.
The humans, on the other hand, seem to be very primitive. I view them sort of like Vikings, large barbaric warriors who drink all day and have very little science or social structure. I hope that when boats are added, humans end up owning the seas because that would fit very much with my idea of them. But, how must the other races see them? Short lived, hairy, pink creatures trying to ilk out a living on the surface in their simple wooden shacks. They're just as likely to go to war with each other as they are with the other races. How uncivilized they must appear in the eyes of the other races. I'm not sure what else to say about them, other than I hope they'll be fleshed out in future releases, because what we have to go with is rather bland at the moment.
Of course, everyone loves the Dwarves. They seem to have the most advanced civilization, possessing the art of steelmaking and having a rather complicated nobility system. Dwarves only seem to be concerned about metals and gems and stone and making things, in general. Other races envy their craftsmanship and the dwarves do a roaring trade with the elves and humans. They overlanders get beautiful stone crafts, and the dwarves get leather and meat and fish and all of the delicacies of the above ground land that they cannot secure themselves. Even goblins, who won't lower themselves to trading as equal partners with the dwarves, admire their craftsmanship and their ability to make steel. The goblins clearly want these things for themselves and actively attempt to capture forts. Dwarves seem like they would rather live in a mountain than anything else, and they certainly don't enjoy the sun as much as other races, so it seems like they would prefer a more isolationist stance than anything else.
Anyway, these are my thoughts on the stock world. There's a lot of missing pieces in my understanding of these societies, so I was hoping that we could help fill in each others gaps. And I hope you weren't too put off by my wall-o-text.