Living Room Ceiling - orange to white

I used to wonder why people found painting a ceiling necessary.  After all, white is white.  And since I'm not a fan of a colored ceiling, except in specific situations, then all of the ceilings I am used to are white, so isn't one white ceiling the same as the next?  The answer is an emphatic NO.  Take this ceiling for instance.  You have wondered why I have painting this ceiling on my to-do list.  Well here is the proof that I am not glutton for punishment (or a martyr as my husband says).

Before:  White right?  WRONG.

 Here is one of the air conditioning registers.  Can you tell, aside from the actual stains, that the paint is very dingy?  This is actually an area that isn't that bad....it gets worse.

 Oh, peachy, orangey, nicotine-infused ceiling of mine...this is why I decided to paint you today........

 After break #2:

 AFTER: (See the little orange stripe in the top left hand corner??  That isn't photoshop people!)

 I forgot how hard it was to paint a ceiling so I didn't make it as far as I'd like...but it is a big room, and my arm hasn't gotten used to it yet. 

I'll let you know when I truly finish this item on my list!