Last week's Eleven Foot Poll recorded an even split between Dwarf and Eladrin for "Favourite PHB Race". Seeing as one of those votes for Dwarf was mine, I'm going to declare Eladrin the winner.
I'm still a bit baffled as to why Eladrin were introduced to 4th Edition. Previous editions were already overflowing with pointy-eared ponces; if your straight-up Elf wasn't your style, you could take a Half-Elf or Drow, both of which have made the jump to 4th Edition, or look into a variety of High Elves, Wood Elves, Low Elves, Sea Elves, or other such aberrations.
Flavour-wise, Eladrin take elves back to their roots as the faeries of Celtic mythology. These are the archetypal fae, who can be mysteriously kind in the same breath as being horrifyingly cruel, who are monsters and angels all bound up in one. You could do worse as far as race concepts go, but it leaves one wondering exactly what's left for the Elves to claim as their own now that the Eladrin are in town.
Mechanically, Eladrin are a mixed bag. Both their "supermodels on steroids" appearance and their Eladrin Education racial (which gives them an extra trained skill at level 1) suggest that they may be aimed at roleplaying enthusiasts more than combat twinks. The stat boosts to Dexterity and Intelligence favour this interpretation, supporting as they do the Warlord, Rogue and Wizard classes.
On the other hand, Fey Step is a beast of a power, granting a once-per-encounter five-square teleport as a move action. That's tremendously powerful in battle, allowing rogues to regularly gain flanking when they need it most, and letting other melee classes invariably assume optimal tanking positions on the first turn while non-melee classes become almost impossible to pin down.
Fey Step needs to be that good; it's competing with some deceptively useful abilities available to other races, and it's doing it as virtually the only attraction of playing an Eladrin. Compare it to the grab-bag of Dwarf powers, which include warhammer proficiency, a resistance to being knocked prone, saves against poison, no speed penalty for armour or encumbrance, and the notably excellent ability to take Second Wind as a minor action.
I'm still uncertain about the place of Eladrin in D&D's spectrum of racial flavour, but mechanically, they're impressing me more every day. If you haven't tried one yet, consider it for the next chance you get to play in a one-off session.