I hate to break up this "Jobs promised me a 3.0 Ghz G5" and "Jobs didn't really promise you a G5" argument with a little logic, but....
(1) At last year's WWDC, the new G5s were NOT released. They were announced. They were not released until September. (And late September at that!)
(2) Steve Jobs certainly did make what I would call a definitive statement about reaching 3.0 Ghz in a 12-month timeframe (i.e., by this year's WWDC). You can argue about whether it was a "promise", or not, but the fact remains his language was not ambiguous.
So, why can't this be the case:
They planned to do an interim update of the G5s. It didn't go as smoothly as they had hoped. So, it's being delayed until now, and tomorrow (or whenever), they will release 2.6 Ghz G5s.
Then, at WWDC, they announce (note the difference) 3.0 Ghz G5s (at a higher price point than the 2.6s...maybe as a new workstation), just like they announced 2.0 Ghz ones last year, and they don't ship them until September?
This seems more likely to me than these stupid all-or-nothing scenarios everyone is getting their panties in a bunch about...