Shades of Gray: Deciding on Paint Colors

I have had this picture saved on my computer for months in hopes that we would find a house and I would be able to pick paint colors and start decorating again.

I love the color gray! This has been a trend in decor for quite a while now, and I have been dying to use it.  Since moving into our house,  I have been collecting paint swatches. 

The problem is, which gray shall I choose?  I thought I could just pick the "perfect gray", but the more I looked at swatches, the more confused I was.  I would pick one color and the second I put it next to another "gray" it would turn blue, green, or purple.  I have gone to buy the paint several times and walked out with nothing but more swatches.

I guess I didn't realize the complexity of the color gray.  

I thought the best thing to do would be to buy the little testers and see which I like best on my wall at different times with different lighting.  I ended up with these 5 on my wall:

From left to right:
Woodsmoke - Eddie Bauer
Silver Threads- Olympic
Dolphin - Martha Stewart
Chinchilla - Martha Stewart
Driftwood Gray - Martha Stewart
Natural Gray - BEHR

Guess what?  After all that,  it's still a difficult decision.  Here they are on a different wall with different light.

Oh, and just for fun, I stopped by Sherwin Williams and bought one more sample (as if 6 wasn't enough) called Magnetic Gray.  This one was recommended by a few designers in magazines and a few blogs.  I really like it and I decided I will use this in our bedroom, which does not help me in my current 1st floor paint search.

Believe it or not, Ernesto has started putting up customers' xmas lights already and will be working everyday until mid-December.  I guess there is no rush to decide on paint colors now is there?  Maybe if I live with the painted samples for a month Ill be able to make a more definitive decision.
Have any of you painted a room gray?  What was the color and are you happy with it?