If you find a good modern translation (Robin Hard is good), I emphatically recommend reading the discourses. Don't cheap out and suffer through some stuffy 19th century translation.
At the other end of the spectrum, I've suffered through some overly-simplified/modernized translations of fiction (e.g. Dostoevsky's the Gambler) that was complete butchery, but I guess this is less likely to occur with non-fiction.