It seems almost mandatory when talking about this film to talk about the failed attempt to start the franchise 5 years ago when Ang Lee got hold of Eric Bana and Jennifer Connelly ... and nobody really cared. It's a common myth that that film "bombed" - while it clearly was not as good as it could have been and was undoubtedly a disappointment both financially and artistically, it still made almost double its budget in theatres alone, but was a very underwhelming film (I skipped it at the cinema and watched it on tv years later ... smart move on my part).
This is the second attempt (which, frankly, smacks of desperation) to cash in on this particular superhero's possibilities and while a better and a more satisfactory experience than its predecessor, it's hardly the stuff to get anything approaching excited about. The set up is that Dr. Bruce Banner (Edward Norton) is on the run, which we find out what for via a very economical opening title sequence (which sadly is probably the best piece of direction during the entire film) - it's been 5 or 6 months since he last transformed into the Hulk and he's chilling out down in Brazil practicing relaxation techniques and wasting away doing manual labour in a bottling factory.
William Hurt is a top member of the Army who wants to capture Banner and Tim Roth is a Russian-born English raised soldier "on loan" from the marines (how ridiculous, what, will he be cup-tied against West Ham and he's just killing time before his big move to Real Madrid? 
) who are the main guys after him. Hurt's daughter is Liv Tyler (who, as the person I saw the film with noted, is looking more and more like her father every day and that is NOT a good thing), who is also Banner's former sweetheart and they all come together in a series of action sequences.
What's good about the film? The pace. It rattles along and doesn't feel anything like nearly 2 hours. Another good thing, in the main (barring the scene in the campus) is the special effects and the action sequences. They're well done for the most part and deliver what you'd expect. The problems though are numerous and most arise from the script.
Firstly, the tone is all over the place. They throw in scenes here and there just for the hell of it (there are at least 3 scenes which are shameless cameos and serve very little purpose other than to put the people - who you only know if you have the inside knowledge - into the film), one scene in particular in a taxi in New York was complete comedy and sticks out like a sore thumb and bears no relation to the rest of the film.
Secondly, the characterisation is a complete joke, there's none at all. Norton's Banner ... we have no idea who he is and that he distances his character from the Hulk only serves to highlight the chasm that exists between the two personalities (I'll get into that later). Tyler's character is even worse, she has a boyfriend who ... gets dropped and is never heard from again to which she never bats an eyelid. Also while I'm all for shorthand with characters who have a previous relationship ... the actors don't even fill in the gaps and there's nothing like the scenes in House of Flying Daggers with Andy Lau and Zhang Ziyi, or Cat Power and Jude Law in My Blueberry Nights to show the body language former lovers have, the level of intimacy coupled with the distance as they've moved on. Roth tries his best but his character is nothing more than a fight-loving hooligan and while Hurt has probably the most developed character of the four ... that's like saying Jessica Alba's latest film wasn't *as* bad as her other ones.
The third big problem is there is very little continuity between Norton's Banner and the creature we see on screen as the Hulk. When you see him battling away, you're detatched, there's very little relation between that creature and the "character" we've been following apart from the odd look to Liv. Maybe it's because Norton's character is so paper-thin, maybe it's because he denies the Hulk is anything to do with his personality, maybe it's a bit of both. What you don't get though is something like the end of Iron Man where you absolutely feel for and like and care about the guy in the suit, even when he's doing battle. It's a big negative.
Despite all that, despite some clunky lines (They make the point that Roth's character is English then have him naturally talking about throwing "softball"s around? 
), despite the allusions to countless other films, it's really very watchable. Not very intelligent, requires a vast suspension of disbelief (especially in the "how did he get there/do that/that makes no sense he can go for a run but not have sex/if he doesn't know if he's going to change or not why doesn't Liv just give him a handjob to test? etc., etc., etc.), despite all of this ... it works, because it's a stupid comic book movie and it does everything it says on the tin. Doesn't make it a great film, not even a good one, but it's fast moving and the action does what you'd hope and expect. All the criticisms above are what stop it being a good film, but none of them ensure it's a bad one. It's alright and probably worth seeing if you like this sort of thing. Just turn your brain off and forget everything you can while you're in there and it'll be an entertaining enough 2 hours which will absolutely fly by.