I'm just letting my divide by zero exceptions loop forever, and lock up the system, for now. At least until I get around to implementing a proper OS-level exception handler.
The same goes for invalid instruction exceptions. Other, more serious exceptions just cause a triple fault and reset the machine, which is also fine, for now.
You aren't likely to run into a divide by zero exception or invalid instruction exception on a regular basis, so as long as you can step through your OS with a debugger, like BOCHS, on the rare occasion that the machine does lock up, you should be fine.
Just put "Handle Exceptions!" on your TODO list..
If you want to save yourself some time debugging, just write a custom interrupt handler for each of these exceptions, and have it clear the screen and write a static message to the screen (or show an image if you are graphics mode).