I just recently rewatched the whole series in light of the news about a fifth film. And there's no changing my opinion at all, the first three are classics. Even the second one, which is actually my favorite, although it does lose points for making too many cute references to the first film.
With a Vengeance though is probably my favorite now. It starts out with a bang and never lets up. I finally got to completely rewatch Die Hard 4 (refuse to call it by it's real title) because my DVD always messes up haflway though, had to finish the last half on my lap top.
Anyways, it's not a horrible film, it has a great first half, so great in fact that the last half of the film really lets it down. Plus Willis just isn't even trying. It's a shame watching his McClane have so much energy in the first three films only to come to this film and watch him phone it in. I really don't have much to say on it though, it does have some positives. I think I'm the only one who likes Thomas Gabrielle as a villian, and I thought Winstead was good as Lucy. But as an action film it just falls short, they never ramp it up in the second half of the film, it's just...dull. And for a Die Hard film that's a real shame.