To put it simply: Awesome game! Bioware really lived up to their reputation as one of the best RPG developers on the PC and Dragon Age Origins surpasses classic RPGs like Baldur's Gate in my opinion.
Combat has been refined from Baldur's Gate. The dialogue voice options are good, but what this game does primarily well is two things. Content, and characters.
Loads of RPGs have lots of contents, But Dragon Age makes the content interesting right until the end. At no point do you feel bored and exhausted.
Characters, they really stand out and you will remember them even after you have played the game. Each of them has their own motivations for why they are in your team. Again, this has been done before, but DA does this all most better than all other RPGs.
For me, Dragon Age wasn't a game. It was an experience, that all gamers should take.