My first thought here is that perhaps the "unimportant" stuff you are arguing about isn't so unimportant. You didn't give any examples, but something to remember is that a small, seemingly unimportant argument can really be about something else. Without a detailed understanding of your situation, I'm going to try and throw out a few ideas...
It's All About Control
Do you and your boyfriend live together? Do your unimportant fights revolve around things that *seem* as silly as putting a new roll of toilet paper or putting the seat down? Do you fight about who takes out the trash? Do you fight about the remote?
A lot of these really small things are less about the issue, and more about control. Perhaps there is a battle of wills going on between you that you aren't aware of. A lot of arguments may not necessarily be about the current issue at all but rather about a need to feel equal, in control of yourself and respected by the person you love.
Why the Effort?
If you find yourself arguing constantly about little things that in your words are unimportant, why do you both put so much effort into arguing about them? What do you get out of it?
Another thing to ask yourself is whether or not there is something that perhaps one or both of you have not let go of in your relationship? A past issue, a past problem? Look for something that would be triggered by what your arguments are about. Most often, when you find yourself arguing about the little stuff, it's because it's easier to argue about who decides what movie to go to then to figure out what is really hurting, what is really causing you pain and anger.
Discuss Your Arguments
My suggestion would be to sit down together, and listen to what each one of you has to say. Start with something you normally argue about and find out what's underneath that stance you take in the argument, what you are feeling underneath it.
For instance, if you fight over the roll of toilet paper...he never replaces it and you want him to (or visa versa). He *could* be feeling that you are trying to control him, and if he does what you ask of him, then he loses some control of himself. (this is JUST an example! :)
There are always issues underneath an argument. You just need to find those issues, and deal with those - not the surface problem.
What do you think of Answer?