I go with EasyWDW for the crowd calendar. Of course, you need to apply some thought if you are doing park-hopping - the crowd calendar alone shouldn't necessarily dictate where you go.
For example, even if Animal Kingdom is least recommended due to morning EMH, it probably will be pretty empty after 4 pm. And even if MK is most recommended on a party night, you still probably don't want to plan to hop there in the afternoon, since transportation and walking thru bag check, tapstiles, and Main Street on a party night will take awhile - it just wouldn't be worth it if you're only there from 4 - 7 pm.