@Kei:
Maybe it's because I haven't seen E7 in years, but I'm having trouble drawing any connections between the two.
Aside from "reluctant young male lead" which describes half of every anime ever.
Let's see…....
Renton Thurston = Simon (though that doesnt really count)
They both start off with mundane lives.
An act of serendipity changes their lives forever.
It has mechs.
The Gekko-go and the Dai Gurren Squad go against the government.
Both animes have a giant moving machine thing that is used as the base/home/etc of both groups.
Both have an old guy that is there for no reason....(at least E7 did, I dont know about Gurren Lagann yet)
Whats her face sort of resembles Talho from E7.
Kamina also resembles Holland, but Kamina was more awesome.
E7 had three kids who bugged the shit out of me, Gurren has two.
The mechas of both animes rely on 'feelings'.
The overall atmosphere is like E7.
Those are the only similarties I've found so far.
@Cap'n:
Eureka 7 always seemed like a giant borefest to me
You must have not watched the entire thing.