1) What are the pros and cons of low voltage and line voltage halogen lights? A friend (who got a degree in electrical engineering a long time ago) said there was no advantage to low voltage, that maybe originally low-V was the only way they came. Is this the case?

2) Is there a standard recommendation for spacing recessed halogens in a kitchen ceiling (the ceiling height is 8'8")?

3) Also, aside from ability to change light direction, why would you choose cable halogens vs. recessed, or vice versa?

I appreciate your help; I'm not having an easy time understanding the essentials of kitchen lighting!