I've been looking at HD monitors from Sony, JVC and Panasonic and noticed they list either P22 or SMPTE-C phosphors. Aren't these phosphor types optimized for CCIR 601 colorspace? If not, then what is the technical difference between 601 and 709? What is lost when converting 709 to 601? Everything I've edited has always been converted to RGB and then output to either 709 or 601 and I don't see that much difference.

You know Xander, this is actually a very good question. Of course, the short answer is that 601 spec is for SD signals and the 709 spec is for HD signals. But what exactly is the technical difference?

For a conversation starter, according to this excellent PDF: "Standard RGB Color Spaces" located at:

http://www.extron.com/download/files/brochure/dvepro_ebro.pdf

"601 and 709 phosphors are practically the same, but the 709 standard defines a different form of gamma correction..."

That entire document is a pretty good read.