Creature listings have also changed. Descriptions are a tad more terse now, and offer less insight in to their ecology than the old 3-ring Monsterous Compendiums. On the upside to this all creatures now have ability scores as a PC would. (STR, DEX, CON, etc...)
Note, ability scores themselves have changed format. No longer are they in the 1-25 range. An open-ended scale is now in place. However the six stats themselves remain the same.
A nice addition is the inclusion of "recipies" for magic items in the Dungeon Masters Guide. This is a part of making item crafting more accessable to PC's. The line of "Craft X" feat is also part of this.