Should I pay attention to Longhorn?

Nope, I shouldn't.  But, if you are a super early adopter, maybe you should.  Straight from Chris Sells himself:

"If you're wondering whether you should be paying attention to the information on Longhorn that has appeared on the web and in the news lately, then you shouldn't be. Longhorn RTM is years away. This is the most lead time we've given on any Windows operating system ever. The reason we did it was so that we could get super early adopters to give us meaningful feedback while we still had enough of the development cycle left to make meaningful changes. If you're not a super early adopter, than Longhorn is just going to be noise that you should ignore 'til the beta hits."