Tough choices to make, Bill. Of course it depends on your needs, like you might want the Twin Task in your car or garage, and the Z2 by your nightstand with a firearm. Otherwise, they would be sooner sold in my book than the others.
So, the TT3C goes first. Nice light, but weaker than the others. Then I'd sell the M6, as long as you have a couple old lamps, so you could use them in the M6LED if you wanted. Then the M8LED because it's too heavy and not that much brighter than the M6LED.
Then the Z2, since you still have the Z3. If weight is a consideration, carry the M6LED or A2 and leave the Z3 at home. Now, whether to sell the M6LED or the Z3 first depends on a few things. You'll get more money for the Z3; the M6LED is more versatile, since you can put in an incan lamp; the Z3 is a better tactical tool. In the end, I'd sell the M6LED first and then the Z3.
That leaves us with the Space Needle II and the A2. I know you want to keep the SNII, but if I could only have one light, it'd be the SF. The A2 is more versatile and easier to carry, thus it's suited for more purposes and I'd part with it last.
Of course, if these are your *extra* torches, rather than your only torches, it might be different.
daloosh