You're planning a 2006 trip then right? At least you'll be avoiding the crowds of this year June/July which are heightened due to the 50th anniversary. If you go to Disneyland with the mindset that you are comparing the two, you'll likely come away disappointed. WDW is a resort community with 4 major theme parks, water parks, entertainment district etc. Disneyland is a different kind of atmosphere a bit more laid back and it's the original. However, there is LOTS to do in Southern California so if you add on beach trips, Universal Hollywood, Knotts Berry Farm, etc you'll ensure that your whole family has a great trip on the West Coast.
I assume you're working with school schedules. If May is a possibility for you, it would be less crowded than June/July. It would even be possible to enjoy Disneyland over a long weekend if you have teacher conferences etc that might allow you to take some October time off.