Since it's such a fantastic series, let's take a look at some good recommendations for anime like Eureka Seven. Many anime are similar to Eureka Seven because of their mech aspects, but not all of these recommendations involve mechs or pilots.
Series like Neon Genesis Evangelion, Gurren Lagann, and Code Geass can all compare to Eureka Seven. In Code Geass, an ex-prince comes into possession of a power known as Geass and sets out to destroy a dangerous superpower entity. Other anime that has elements of adventure, mecha, and sci-fi like Eureka Seven include Last Exile, Fractale, and RahXephon.
With your votes, you can determine which of these similar anime to Eureka Seven rise to the top of the list. If you happen to notice a good anime isn't here, feel free to add it!