To explain my suggestion to increase blue gain or decrease red in the color space settings for blue, chelhydra noted that blues looked kind of purplish on his set, which means there's too much red in blue.
My blue color space setting has a bit of red in it, so my first thought would be to try to reduce the red there. The color space settings are somewhat limited in their range though, so if it still looked purplish, the only other thing to do is make blue higher. Since blue is already maxed out in the color space settings, you have to mess with the white balance. This does mess up the white balance a bit, but no TV is perfect and you have to make compromises in making adjustments
(Admittedly, I'm not too good at knowing which
compromises to make yet.)
Making those changes will make blue have less red in it, but then the problem is green. If you have too little red, the blue will switch to having a slightly green tint.
Now making this more complicated is that in addition to the "color", there is also the "brightness". So even if blue is the right color, if it's not bright enough (relative to the other colors), there will be a perceived lack of blue, if that makes sense. When you reduce red in the color settings, you also reduce the blue "brightness" (since brightness is roughly related to the sum of all the colors). This is more or less what happens when you adjust the color control, reducing it reduces the brightness of all the colors.
And now back to the Samsung A550
. To get the white balance correct, I had to reduce the blue offset and gain slightly in the white balance setting. This makes the blue "brightness" too low. Cranking up blue in the color space setting helped a little, but it wasn't enough, plus the color of blue was slightly off. So this is where I had to compromise a little bit. No amount of messing with the color space settings got blue to be the right color, so I went for getting the luminance more correct.
I also read that getting red correct would make green and blue follow, and that the eye is less sensitive to blue than the other colors, so I settled for getting red and green correct and didn't worry too much about blue.