For me, Eberron is neat because it deals with one of the things that has always bothered me about most Fantasy Settings, and D&D in particular.
Why is it, that in a fantasy setting with magic, which is an unlimited resource, where you can make permanent magic items, that 99% of the population lives as dirt scrabble farmers or medieval town peasants? Why are the streets of Waterdeep filled with beggars and poop (human and horse) like 1300's London?
Eberron is built on the concept that any sufficiently advanced magic is indistinguishable from Technology. Trains, Air Travel, restaurants, Indoor Plumbing, the works.
Magic is a commodity, and can be bought and sold like any other service or good.