Mouseferatu said:Depends what you mean by "support."
If you mean "several campaign-specific books, followed by multiple smaller books and/or regular features on DDI," then I'd say just Eberron, FR, and maybe one new one.
If you mean "a single hardcover book (or even one large book with multiple settings), followed by occasional DDI articles," then I'd have to say almost all of them.
Listen to the undead rodent on this one (I don't really care a lot about FR, but it's too popular to ditch; I'll grab the player's guide purely to raid for mechanics).