Troy is an action movie trying to extract all the influence of the gods from the Illiad in an attempt to rationalize the story as an historical event.
The action is grandiose, the story interesting, the scenario has a good pace, and the special effects are still acceptable by today's standard.
Brad Pitt, as Achilles, is at his sexiest and his most arrogant. Is rendition is probably close to what a invincible demigod would be like. Eric Bana is probably at his best in the role of a good hearted Hector. Brian Cox, as the power hungry Agamemnon, makes us hate his character like only he can do. Diane Kruger seems to struggle in her role lacking some fluidity. Orlando Bloom, as lacking talent as he does, probably did his best performance as the romantic, clueless, charming and cowardly Paris. Sean Bean is perfect as the valiant and cunning Odysseus. And finally, Saffron Burrows moves us with her lovingly tragic rendition of Andromache, Hector's wife.
Now, for a few bad things. The fighting, either man to man or on large scale, is not realistic, and neither are the armors, although they mostly respect the style of the time. Also, the rowing wouldn't be functional as depicted. However, most of that is just nitpicking, and the really annoying bit is that the dialogs, while not being dull, are weak for the most part.
If you want plenty of action in the time of the Greeks with beautiful people as actors, this should satisfy your needs. If you're a Brad Pitt or Orlando Bloom fan, it's made for you.