Just like the rest of them, Die Hard 4.0 (Live Free or Die Hard in the US) is about the right guy at the right place at the right time (or was it wrong place at the wrong time...), stumbling across the plot of an evil genius and doing what it takes to save the day. Bruce Willis kicking ass and taking a beating at the same time. That guy is so cool.
I loved how only minimal computer generated effects were used for this movie. Either that or the CG people have just gotten so good at what they do that I can't tell the difference anymore. Well there actually are digital effects especially towards the end but overall there's a gritty old-school feel to it so it feels right at home with the rest of the series. Spielberg could learn a lesson from this and apply it on Indiana Jones 4.
The movie is aware of how crazy ridiculous action movies can be, knows that the audience expects nothing less than that sort of outlandishness from a Die Hard movie, and then takes advantage of this liberty to push the envelope and give us some of the most awesomely preposterous action sequences imaginable. So when John McClane, faced with a massive collapsing highway interchange, jumps off of an exploding truck and onto the wing of an airborne fighter jet-- just moments before the pilot pushes the eject button! -- it doesn't draw a dismissive reaction of incredulity, but is welcomed into open arms with a big stupid smile on my face