Spider-Man still holds up, in my opinion--it's just timeless. I just watched last night with all the latest news/rumors, and you can take the script, shoot it today, and it'd still play well. Spider-Man 2 less so, but its the performances & chemistry between the cast (and success of the first film) that really pulls that one together.
Unfortunately, the marathon really does fall apart with Spider-Man 3. And you can almost immediately tell. The movie has shades of greatness--and I don't think its issue is Venom, or even Topher Grace--it just doesn't hit the heights anywhere near as high as its predecessors.