Ah! My Goddess, thats a good comedy romantic type show
there is the OVA's Movie and TV series, where to start is a good question
The TV series is the most recent being this year and last year and is closer to the manga, although the director ghoda
does take some liberties in bringing characters in earlier than normal as the manga is longer thus would take too long
to introduce them.
OVA does start from the manga but to make it have an ending as its 5 ep ova it creates its own storyline for the ending
as it was made in '93 or so and the manga was still relatively young
the movie has its own story and is set 3 years after belldandy and keiichi first met and introduces a character not seen
in the manga to date (well two characters actually)
But i recommend either the OVA or TV series (s1 26 eps and S2 22 eps (2 eps of s1 are dvd specials)) as that will
introduce the characters first, then you can move onto the movie and the other anime which you havent seen
then there is the mini goddess, just a heap of random adventures, quite funny :D