Assuming I upgrade the setting that's served me since 1E (and it's a coin-flip, ATM, but not because of 4E):
Humans: I strongly prefer humans to be the baseline, and it shows. Humans cover the vast majority of the planet, come in all sort of races (as on Terra), and have too many states to enumerate here. A lot of the 4E "Races and Classes" bits sound like they'll port well with only minor flavor changes.
Eladrin: Long called grey elves, the eladrin are celestially touched. They are without souls, but their spirits are reincarnated when they die. Grey elves are magically talented, but their predisposition to isolationism (their nation is set far from human lands) has kept them somewhat static, as a race.
Elves: Almost a forgotten race, the elves are a splinter sect of a splinter sect (that middle group may fall into either elf or eladrin, I'll have to wait for the book). The elven race lived near humans and eventually fell prey to their wars. The wood elves have spent most of the last half-millennium in slavery to a despotic empire. Those who have escaped live at the borders of the empire, seeking to free their families. The once peaceful race has turned more martial and territorial -- rarely do outsiders survive long enough to realize they've entered elf territory.
Dwarves: Dwarves fall into two nations. The first is a religious people deeply dedicated to their gods. They have reputations as hard workers, masters of any craftwork (especially smithing and masonry), and folk who prefer to be left alone.
The second, more northern, nation have fallen away from (or been forsaken by -- depending on whom you ask) their ancestral gods. They have retained their pride is craftsmanship, but otherwise tend towards deceit and trickery. They are also known to be expert wizards, though their focus tends toward enchanting items.
Hobgoblins: This is a warrior race. If you are fortunate, you will deal with the Dthek hobgoblins. Their people are honorable, if brutal by human standards. The Dthek still seek to reclaim their desert kingdom from the undead horrors unleashed by a war centuries past and they revere some of the same, benevolent deities as the humans. Other hobgoblins regularly higher themselves out as mercenaries of the highest caliber. While their cost is steep for those seeking their service, it is their targets who pay the highest price, for hobgoblin cruelty is legendary.
Trolls: Not the scraggly green sort that are hard to stop, but a hearty and intelligent race with a tie to the plane of shadow. Trolls are well known shadowcasters, which casts suspicions on their motivations at times. This race has only recently made its presence known and has many secrets.