A sacred cow to many otakus, "Neon Genesis Evangelion" has been oft hyped as a must-see event and some sort of seminal work of anime.
Don't buy it for a second.
Perhaps you could consider this a seminal work of anime, though not in any sort of positive way - it utilizes (or maybe establishes?) several of the frustrating formulae that bog countless other anime down. Whiney, weak protagonist dragged into things against his will? Check. Emotional and generally ineffectual female characters who serve no real function but to be saved by the male characters? Double check. Static and utterly unconvincing archetypical characters all around? Triple check. Barely coherent ramblings and various tidbits thrown around to create the illusion of some deeper meaning? Oh yeah... it's got that in spades.
The anime has some impressive visuals and some really visceral moments, but it's weighed down by so much baggage that it's ultimately frustrating more than entertaining. In all liklihood you'll end up hating every single character, as there's nothing to like about any of them. That particular sin can be forgiven if the plot is captivating enough to pull the weight of the show alone (or if the characters are deep enough that we don't need to like them to be interested in them), but Evangelion tries very hard to be character driven without any particular character capable of driving it.
Could anybody be as annoyingly self-absorbed as Asuka? Could anybody be as weak-willed as Shenji? Could anybody be as cold as the commander? The only character that really seems to be believable at all is Misato (sp?), if only because she seems to in some ways resemble an actual human being with a normal range of emotions.
Probably the most frustrating thing about the series is the way people jump on its mish-mash of religious references and random postmodern crap. The pseudo-intellectual crowd eats this stuff up - "hey, a Christian reference, it's DEEP! I'm SMART for spotting it!" - and they grab onto this jumble of allusions as a convenient way to brush off any critics as "not getting it."
See, there's something you should stop to consider - maybe there isn't actually anything to get in the first place.
Evangelion starts slow, ramps up a bit, and collapses and dies in the home stretch. The primary story arc is never resolved in a satisfying manner and the backstory is left with huge voids. Had these elements been executed properly, the series could've perhaps been salvaged on some level, as it would have at least been satisfying from a plot perspective. But the pacing of the series is so incredibly slow at times that you feel like you're never getting anywhere, and just when you start to think you might be the final episodes of the series step in to ruin it.
The heavy-handed postmodernist conclusion of the series, where we take an incoherent stroll through the main character's shattered psyche, reminds us that we all define our own realities. If that's the case, pardon me while I go define a reality where this series never even existed.