How important is the Centre Speaker ?

Something like 60% of voices come through the center, so to me very important. You could make your receiver shift this audio to the fronts, but I personally don't like that.

Very important. I think people should use the same speaker that they are using for their mains for the center channel.

Not important at all to me. I've tried many different center channel speakers, and found no center channel to be the best option. I prefer the 'phantom' center channel. I believe if your front speakers image properly, the center speaker only messes things up. That's my $.02.

Depends on your room and seating, if you have poor seating arangement with few good seats...a center is very important. Nothing worse than watching a movie and having the voice come at you from left or right of the screen.

In larger room with great seating flexability you may prefer no center speaker at all because voices will be center as they should be.

Dave