A must see:
1- Trigun (funny, good action, great story, watch for a black cat in every episode)
2- Berserk (I agree with Berserkfan though...there is so much left of the story. It's gory, slight nudity, and A LOT of violence)
3- Blue Gender (Good action, gory, good story, gets really slow at times but it's worth it)
4- High school of the Dead (ZOMBIES...if you can get past the fanboy parts, good action, great story, and ZOMBIES)
5- Attack on Titans (One of the best I've seen in a while, great action, good story twists, very entertaining overall)
When you have time/bored:
1- Neon Genesis Evangelion (Original ending SUCKED but the overall story was awesome, watch the original series but skip the last two episodes and move onto the new stuff)
2- Cowboy Bebop (funny, good action, decent story line)
3- Samurai Champloo (another funny one, good martial arts, good story)
4- Gungrave (twisted interesting story, great action, kind of gory)