How helpful are neon/led lights on the rims, while riding at night? Recently I saw few cyclists at night with blue neon lights attached to the spokes on their rims. They just kept one each at the back, so it wasn't that effective. 

But having at least 2 of such lights (both front and back) can make a rider very visible at night and avoid possible dangers.

The riding style I am talking about is for both commuting or trailing at night. 

How effective are these lights?
The motion of the light is what does the work, the colour is less important as long as its bright.  A valve light will describe a "flattened corkscrew" through the air and is obviously different to any other vehicle on the road - which means you get perceived by driver's conscious brains not just their subconscious or autonomous brains.  

These things are brilliant because they're not powered, and reflect a lot of light.  They're also lightweight and forgettable.

http://www.dx.com/p/bike-wheel-spoke-abs-safety-reflective-tube-reflector-grey-12-pcs-228130#.VplvhW8y-Cg



Check your legalities too - here its illegal to show a blue light on the road at any time unless you're police.   Likewise green lights are reserved for doctors on urgent medical callouts (although this is very rare now.)   

Anyone can run a flashing or steady yellow light in any direction, but red lights can only show to the rear and white lights can only show "in the direction of motion" which is why car reversing lights can be white.

The same rules go for reflectors, which means my white spoke reflectors are "technically" illegal because they can be seen as white from the rear.

"Ice white" headlights are in a fuzzy area, as are illuminated adverts on buses and taxis that feature these specific colours.