There are so many sets of circumstances that can lead to conflict in the classroom; the first step is to identify the cause of the problems. If the conflict is the result of a personality conflict between a few students, arranging for seating as far apart as possible may be beneficial. If the conflict is between an isolated student and the teacher, a change in class assignment may be the only real solution. I dealt with large numbers of the types of students bullgatortail describes in two of my classes last year. The good students in those classes didn't get the educational experience they deserved out of the classes, and I retired at the end of the year! (I had other reasons for doing so besides the obnoxious students, but their behavior certainly helped form my decision!)
One of the reasons I gave up on teaching in the public school system was the never-ending problem of disciplining students in the classroom. One particular school had a weak administration which didn't seem to mind that the middle school classrooms were disorderly. Students who came to school to learn and get an education were still in the majority, but the small number of kids who came to school because they were forced to, and who refused to accept class rules and normal social behavior created problems on a daily basis. (This was a rural district with mostly very poor families.) Giving the students detention and other forms of punishment only angered them more, causing even more outbursts of temper--further eliminating class structure and the primary goal of a classroom: teaching and learning. I generally tried to calmly escort the student outside the classroom and firmly tell them that the next problem would lead to them being sent to the office. But many middle school kids don't respond to being treated in an adult manner, so failure in this respect was the norm. Transferring these types of students to another class only passes the buck; guidance counselors seem to help in the short term; and parental conferences occasionally ease the situation. Just realize that some students will not adapt to classroom behavioral expectations, and many will never outgrow their temper tantrums and anti-social behavior. All schools need "time-out" areas or In-School Suspension classes for such children, just so that classrooms can remain in an orderly, learning environment.
I have this problem in one of my classes right now. A girl in that class has a very short fuse and becomes extremely angry over the smallest perceived insult; I say "perceived" because some of the things that she gets angry about are really trivial. She slapped a student and chased him out of the room because the paper wad he was throwing at the waste basket hit her instead. (And, no, he did not intend to hit her; I witnessed the incident). I reported her to our assistant principal, who had a conference with her father.
One other thing I have done is refer her to the STARS counselor. STARS, which stands for Students Taking a Right Stand, provides counselors who meet once a week with students who have been referred to them for anger management, drug problems, or other issues.
I've seen no improvement in her behavior yet, but I'm hopeful.