Tengen Toppa Gurren Lagann has incredible animation, a plot that is well-thought-out and well-paced without being more complex or DEEP than it needs to be, Awesome MomentsOnce an Episodeat least, and the most awesome (and humongous) Humongous Mechaever.
Everyone in this series is manly as hell, the women alone probably contain more testosterone than a New York high school in the spring.
Tengen Toppa Gurren Lagann isn't just awesome within the show but the show's very existence is awesome. Once, the anime community was plagued by it's predecessor, Neon Genesis Evangelion, with it's dark, hopeless influence, blocking out any ray of hope or happiness. (Not saying NGE is bad. IT's good but it's damn frightening.) Then, along comes a show that defies everything it's older brother said before it then completing what NGE did before and Reconstruct the Mecha Genre.
To give you some insight about what I said above, I've had a few suicidal thoughts over the years, firmly believing that life was just one endless gauntlet of despair. Then, I watched this show, seeing the characters go through hell and back with a smile on their faces even as they died. And as I watched, I began to feel this burning feeling inside of me, a warmth that filled me from head to toe. And this warmth made me feel glad to be alive as the show brought back all the good memories I had (unlike Evangelion which brought back the worst memories). Now, I never get those thoughts. Some had their depression cured through the above mentioned show but I owe my happiness to Tengen Toppa Gurren Lagann.
In fact, Simon is Shinji done right. Whereas Evagelion stopped after destroying everything Shinji held dear, leaving him in a broken state beyond repair, Tengen Toppa Gurren Lagann drilled through the wall that stopped it and had Simon evolve beyond who he was, becoming a better person overall.
Tengen Toppa Gurren Lagann holds a special title as the only show this troper has stayed up until seven in the morning to watch (I was originally going to stop after the defeat of Lordgenome, but I just had to see what else was going to happen). Everything about this show is wonderful. The animation is, Episode 4 notwithstanding, solid at worst and amazing at best. The characters are great and most are well-developed (In more ways than one), with only a few (Namely Artenborrough and Cytomander) that I found annoying. The mecha themselves were cool and the fights involving them even moreso. Since the few anime I'd been introduced to by then I wasn't too fond of, and typically wrote off as "edgy, cynical crap," seeing such an idealistic and hopeful series was a pleasant surprise. Even after viewing the series multiple times, I still find all the Tearjerkers (Especially The wedding), all the Heartwarming Moments (Especially Kamina's final reappearance), and all the Crowning Moments of Awesome (Especially the entire final battle sequence) just as effective as on my first viewing. And to top it all off, It's got a great English dub, too. So don't worry about having to watch subtitles if you're too busy to remain glued to your screen, even if the show itself will make you stay there a few times.