There are several reasons to shave one's pubic hair:
1) It's hygenic to do so. Shaving pubic hair prevents the build-up of germs, body fluids or other substances in that general area, thus contributing to the person's general health.
2) It lessens the scent that can develop in the area of the intimates. Females especially, as they have their period, can find a distinct odour due to period fluids sticking and drying in the hair.
3) It can be aesthetic to shave. Smooth skin without the mar of hair is appealing to many people.
As Jessica said: you will not find "skin irritated or itchy later on if you do it correctly". However, skin can itch even if shaving is done properly with a clean razor, and maybe some gel, as the skin becomes slightly irritated due to the rapid regrowth of the hair. Pubic hair grows much faster, and sometimes more courser as well, than ordinary hair found on other areas of the body.
In conlusion, I am greatly in favour of shaving.