The BARC Troopers on Kashyyyk were probably my favorites... The Scout's armor has always been a design I liked, and seeing it used on some kind of specialist group in camo is kind of neat.
I thought the Clone designs in ROTS were nice though... A different time and all that. Clones being given individuality by their Jedi leaders... It tied in with the notion of "emotional attachment is forbidden" among Jedi really well I feel, and it's one of those little things that just got glossed over. The Jedi grew a bond with their Clones, as we see with Obi and Cody, only to have that trust and closeness be betrayed wwithout them having the foresight to see it coming.
It's really no different than Obi-Wan being blind to Anakin's thoughts and emotions... His "love" for Anakin never lets him see what Anakin is truly able to do.
So the different colors, to me, really represent that different time of individuality among even those who have none.
Come time of the classic trilogy I'm of the breed that feel they're no longer Clones... Individuality is now supressed by the uniform, though it's there underneath. The irony of that really sits well with me. That Clones strove for individuality, and expressed it with names and unique looks, but yet in the Empire's army the military is only individual under the armor... On the outside they now appear the mindless drones their Clone predecessors supposedly were. That's deep to me.