Greetings!
Heh, in my world, I have Elves, Dwarves, and Halflings. I don't think anyone who knows much about my world wouldn't say that it wasn't an interesting, detailed, imaginative world. I also have numerous other races that are quite prominent throughout the campaign, such as elephant people, hippo people, wolf-people, deer-people, as well as Ogres, Trolls, tiger-people, and several very unusual, unique races.
Elves in my campaign are distinctly different from humans, and are generally entirely superior creatures. They are majestic, lordly beings. Wood Elves are more subdued, but they are still obviously enchanted creatures of magic, and very different from humans, or anyone else. Elves have never retreated, but they have had entire kingdoms broken to the yoke of slavery, rape, and fire. But the elves have never retreated, and in fact are very proud, even arrogant, and ambitious and self-willed.
Dwarves have experienced savage wars, and have lost several ancient mountain kingdoms, but others have prospered, and new ones are being founded. Meanwhile, many dwarves have also migrated into human communities, and have fully integrated with human society, complimenting human communities very well. Some populations of dwarves have molten steel for blood, and can breath fire, while other tribes of dwarves regenerate, and have numerous enhanced earth or fire properties. There are sophisticated dwarven kingdoms, and there are also more primitive, savage dwarven kingdoms that live in rugged mountain kingdoms to the far north, where they perpetually fight huge wars with giants, trolls, and beastmen.
Halflings are a durable race, who have a unique culture of their own, but they have also migrated to other realms, and have adapted to different climates and cultures. Some Halflings live in bucolic, Edwardian romantic environments, while others have become very urbanised and live in sophisticated cities, adopting many aspects of the host culture with their own. Still other Halflings are barbarian tribes and live in the forests, either in an African Masai manner; a Celtic manner; or a forested Germanic manner. There are entire populations of educated, urbane halflings that live as slaves to sophisticated human kingdoms. Meanwhile, out in the distant east, there are wicked kingdoms of humans and trolls that keep herds of Halflings as slaves and food. The Halflings are raised to be illiterate and stupid, and barely able to even speak. These Halflings are kept in herds, and watered, fed, and eaten as needed. Whole clans are used in breeding programs to make Halflings that favour certain coloration or general traits. They are used extensively as agricultural and mining slaves, as well as for domestic and urban use.
The other races, of course, are even more diverse and strange. It seems to me that a Game Master can make any and all such races interesting and vivid. There doesn't seem anything wrong with such races, but one must remember to play them with depth, character, and flavour. They have to be unique, interesting, and special. They have to be detailed, and played well. Doing so consistently will not only build respect from the players for the races, but also repsect for the Game Master's world integrity, and the races themselves, as distinct, interesting races.
Semper Fidelis,
SHARK