And i should watch the FMA or FMA Brotherhood ?
To explain, both are adaptations of the same source, but the former, FMA, was made before the source manga was complete or even really started its main plot, and thus creates its own ending. Brotherhood was an adaptation made as the source manga approached its end (though even then it only ended a month or so after the manga, which is crazy when you know about cartoon production times), and thus accurately adapted it. However, Brotherhood was made under the assumption that a large part of its audience would have already watched FMA, and thus goes through the events shared by both at a faster pace and in less detail than they deserved. Thus, people say that the first anime, FMA, handles those events better than Brotherhood, but the later events that Brotherhood adapts are generally considered more interesting than the path the first anime takes after it deviates from the manga.
For the sake of simplicity, though, I recommend just watching Brotherhood.
Anyway, one difficult thing about generally recommending anime is that it covers a huge variety of genres, so it's comparable to recommending books or movies without any genre being specified. For example, Fullmetal Alchemist is a young adult action adventure fantasy serialized series, Cowboy Bebop is an adult sci-fi episodic series that can adapt different genres in different episodes, Black Lagoon is basically an adult 80's action movie in episodic (in arcs) anime form, Death Note is a young adult murder drama serialized series, and Spice and Wolf is a young adult romantic medieval economics episodic series in arcs (yes, really).