I'll be honest, there aren't many that are of the quality Fullmetal Alchemist was. I'm sure you have seen Death Note, so I'll just mention some that I really enjoy.
FLCL is just fucked up and awesome, definitely check it out since it's very very short.
Elfen Lied. Very bloody and fucked up anime about girls who are monsters. After one of them escapes and suffers a bit of amnesia, she is rescued by an incestuous couple of cousins who take care of her. Having a schizophrenic girl in their home is the least of their problems. Did I mention it's VERY BLOODY? Beware if you really really like puppies. Oh and lots of naked 12 year olds...
Last Exile. About a young girl who is the key to unlocking the last "Exile." Vague, I know. Great fantasy show about two nations that are at war and the people trying to end it a different way.
Gungrave is one of the most badass animes I've ever seen. Harry McDowell is how a villain is done right.
Samurai 7. Based off of Akira Kurosawa's Seven Samurai. Excellent show.
Rurouni Kenshin is an excellent samurai anime that has a couple good movies you can check out. The show does decline in quality as it goes on tho....noticeably.
Trigun. I'm sure you've seen it, so I won't even bother persuading you to watch it.
Ergo Proxy. Futuristic cyberpunk show with some of the best art you've ever seen on an anime show.
Love Hina. Sure it's a romance anime, but it's cute and fun. (Near or Shinigami will probably take away my true otaku card with that response...)
Neon Genesis Evangelion. High concept, influential mecha anime. Just ignore the last episode and watch the movies instead

.
Fist of the North Star. One of the best of the best. I hope I don't need to describe it to you since the mere mention of the name should make you want to watch it. It's THAT good.
X. Yup, just "X." It's about two sides that fight for good and evil who can control battlefields so the real world is not harmed at the expense of their fights. Prophecies and ultimate showdowns galore. Lots of fighting. Ignore the movie, it's too short and confusing.
Ranma 1/2. Yeah...I said it. Ranma 1/2

. It's about a boy who accidentally fell into a cursed river and now whenever he is splashed with cold water...he turns into a girl. A hott girl. Watch it. Old, but awesome nonetheless.
Cowboy Bebop. Yes, it IS overrated. I know...but god damn is it a fun show. If it weren't for Bebop, half the posters in this thread probably wouldn't be watching anime shows. It's a gateway anime...beware
Berserk. If you like violence...you're welcome
Galaxy Express 999. The holy grail of anime for me. One of the best shows I've ever seen and one of the rarest. It takes place in the Captain Harlock universe and features many recognizeable faces including the Captain himself and Emeraldes. It's about a boy named Tetsuro seeking revenge for the death of his mother and his journey to obtain a machine body for himself. The anime is condensed into the first movie, Galaxy Express 999, and a new story is told in Adieu Galaxy Express 999. Oh man, I get goosebumps reminiscing about these two. I so desperately want to get my hands on them again and the show, but I haven't even found them on the internet. Even torrent sites.
http://www.youtube.com/watch?v=TQr-fnhGUes
The Melancholy of Haruhi Suzumiya is one of the funnest animes I've ever watched. I really recommend it if you like animes that are...well...fun
http://www.youtube.com/watch?v=7p--8CPT738
http://www.youtube.com/watch?v=JeR8y...eature=related
Also, while you're out there looking for anime stuff to watch. I always without question recommend any and all Hayao Miyazaki films and Grave of the Fireflies.