Not surprisingly, I learned of Ah! My Goddess (also referred to as Ah! Megami Sama and Oh My Goddess!) after hearing about it from a couple friends... and then I subsequently forgot about it until I saw it ranking high on a couple anime information sites.

This series is "cute" and "playful". There is a lot of nonworded acknowledgements between characters and a lot of just plain "nice" moments. If you don't like the aforementioned in large quantities, I suggest you steer clear of Ah! My Goddess.

Genre: Comedy, Romance, Fantasy
Episode count: 1st Season: 24, 2nd Season: 22. There is also an OVA, a movie, and a "kid's" series as well.

The manga tells the story of college freshman Keiichi Morisato, who, because of his pure heart, has been chosen by God's computer system to receive a single wish. The angel-like "goddess" Belldandy is sent down to Earth to ask for his wish, and tells him that he can potentially wish for anything that he wants, from becoming a billionaire to destroying the world in an instant. However, Keiichi thinks that this entire meeting is a prank being played by his roommates, and so he wishes for Belldandy to stay with him forever, which, much to Keiichi's surprise, she does gladly. The manga follows their relationship as they become closer to each other.

My Addition: The recent TV series, seasons one and two follows the manga closely.

Opening theme (1st Season): "Open Your Mind" by Yoko Ishida
Closing theme (1st Season): "Negai" by Yoko Ishida (eps 01-12,24)
Closing theme (1st Season): "Wing" by Yoko Takahashi (eps 13-23)
Opening theme (2nd Season): "Shiawase no Iro" by Yoko Ishida
Closing theme (2nd Season): "Bokura no Kiseki" by Yoko Ishida (eps 01-11)
Closing theme (2nd Season): "Koibito Doshi" by Jukai (eps 12-22)

-This is a pretty layed back series and just something to relax to.
-The character development is interesting and the plot is also quite amusing.
-It isn't a standardized story, in my opinion, and you might actually be able to relate to some of the situations that arise.