Ok, that's a fair bit, but this thread is way off topic now and in line to be considered Hijacked. No one is in trouble... yet.
Let me remind everyone of the site rules are to make a new thread if you want to go on to a different topic. Let's remember this and get back to the topic at hand.
As to the Blue glow (red for Klingons and green for Romulans, etc), it is both "Eye candy" to make a ship look cooler, as well as having a function.
The Glow is from hot Plasma that runs through the Nacelle. The plasma is contained inside tubes in the form of a grill (several tubes). The Plasma is "charged" with energy by the matter/antimatter annialation in the warp core, which then is fed into the warp coil(s) inside the nacelle. The plasma releases the energy into the coils as it travels along one side of the warp coil allowing the coldness of space to cool it down and vent off radiation so it can be fed back into the warp core at safe temperatures and safer levels of radiation. Plasma is returned back into the system on the opposite side of the warp coil. This cooler plasma does not have a glow effect, as the glow is actually the tubes glowing from being super hot do to the hot plasma inside them. Also note, that the Nacelles, when shut down may still glow, this is both because of the plasma on the outer tubes is still hot, and/or, with TNG and more recent versions of Nacelles, the radiated plasma tubing area has marker lighting to ward off possible accidents involving shuttlecraft and such. The blue is a visual warning of deadly radiation and plasma within the area. The Plasma itself causes the tubes to glow blue, but the lighting was added as a warning system even when not in use. At times when there is no glow, is because of total power loss to that nacelle, which also is absent of hot plasma. And one final note, the Galaxy class (and vessels sharing that type of nacelle design) have 2 warp coils inside a single nacelle. The cooler plasma is fed back into the ship in the middle of the nacelle, and this is why both sides of the nacelle glow, as opposed to the older TMP era nacelles, and even the Sovereign Class Explorer.