The effects in the original trilogy (except for the CGI ones added in the special editions) actually hold up very well in my opinion. As for the prequel trilogy, I would recommend watching all of them before starting on the original trilogy. "The Phantom Menace" and "Attack of the Clones" may be mediocre, but they definitely have their moments. Also, unlike many people, I thought "Revenge of the Sith" was actually great except for some of the performances and dialogue.
