Door facts 
-Minecarts will not move through doors. Water will not pass through either, useful for flood control or underwater paths. Another practical use of the door's water glitch is to leave a door open as an entrance to something underwater that is water-free on the other side.
-Doors placed on doors will be lost.-It is impossible to place doors on ice blocks, glass blocks and snow.
-Iron doors can only be opened by a switch/button. (A wooden door can be opened by both power and by either left or right clicking. Only right prior to 1.4.)
-On SMP, doors sometimes open and close quickly.
-If your computer is very slow, sometimes doors might open and then close.
-If a Player is being chased by a Creeper and then closes their door to the House, the Creeper won't explode and will remain idle near the door until the player reopens the door.
-It is better to use an Iron Door to protect Villagers when they're in their house because it is very hard for a Zombie to break in.
-From the 1.3 update, zombies can knock down wooden doors on any difficulty.-After snapshot 14w02b (Update 1.8) the recipe gives three doors in place of only one.
-Villagers will go into any door in a Village.
-As of Snapshot 14w32d there are different varieties of doors for the different types of Wood (for ex. if you put 6 Spruce Wood in a -Crafting Table, you'll get 3 Spruce Wood Doors.)

[size=14pt]My opinions:[/size][size=14pt]I think its great that there are more doors, even if they are ugly.[/size][size=14pt]the more doors with unique id's allows texture pack creates to make an unique door for every theme.[/size][size=14pt]i think that the doors should operate like paintings, one recipe with a random theme on place.[/size][size=14pt]i think it will not be added to old texture packs(discos) as many people like the idea  one door.[/size]