I'm at an odd place. Part of my brain really wants each film installment to be great, but another just wants both the Fox and Sony Marvel franchises to die swiftly and go away. Seems like Fox has been recovering from their mid-series slump (X-Men & X2 being good, The Last Stand & Origins: Wolverine being downright awful, and First Class & The Wolverine seeming to recover a bit) -- especially compared to Sony's Spider-Man, which seems to be falling apart while they focus on franchise building without caring about the strength of the foundation.
But where Sony pretty much has Spidey on lockdown in perpetuity, Fox is at an (admittedly small) risk of losing their rights back to Disney. As such, there is a constant battle going on in my mind over the X-films; even when they do deliver, part of me is disappointed by its success.
The Spectacular Spider-Man isn't merely the best, it's the only great one.
Loving treatment of the source material without stagnation, great fluid action sequences, wonderful voice talents, poetic structure, actual character arcs (if you can believe it!), and it very effortlessly introduces a great many of the noteworthy Spidey rogues in two seasons. It also gives a great simplified reason for them to co-exist. Best of all, the series never stooped to dumb itself down for the kids. It had a clear enough tone to be accessible to everyone, but had a complex enough take and patiently crafted arcs (unlike Ultimate) to keep adults interested.
They also managed to make Electro and Sandman very sympathetic villains. They were so often depicted as being fairly two-dimensional in previous cartoon incarnations.
Who doesn't love when the symbiote used a sleeping Peter to trash the Sinister Six? Subtle and menacing. It wasn't in-your-face. He was brutal, and he didn't say a word. They didn't need to have him saying anything in an evil voice; they didn't need to have him breakdancing down the street. Organic, subtle, effective story and character development.