While it is true that many schools only have the Monday off, there are also many schools that have the entire week off - i.e., the week that includes the Monday Holiday. For 2004 that would be the week of 2/15/2004. (2/16/2004 is the Monday holiday. Washington's birthday (2/22) is not a national holiday, and there is no reason to avoid it in 2004). Therefore, President's week (2/14 - 2/21) will be busier than either the week before or the week after. If your dates are flexible, my advice is to choose either the week before or the week after.
That said, going President's week is not all that bad if you plan ahead. We've been several times during that period. Stay away from the MK on the weekend days (Saturday and Sunday before the Monday Holiday) as well as on the Monday itself). If you do that, you should be just fine. A friend of my SIL recently described the MK on President's Day as "stroller gridlock". They had to leave and were disappointed at the several "wasted hours". We were at WDW the exact same times, but wisely visited another park on President's Day.
Enjoy your trip!