Panther was awesome, don't get me wrong, Expose is a revolutionary tool, and that alone would have almost made Panther worth the $129. However, Jaguar to Panther was no where near the same magnitude...
When Mac OS 11 is released it will be a signifigant jump from X. Similar to (although probably nto quite as signifigant as) the jump from 9 to X. The way they have been doing it (10.1, 10.2, 10.3...