I've only been an Apple geek for a year now (at age 46), but I really do like the improvements in Leopard. I think it was well worth the $109 I paid Amazon for a copy. (free shipping, no tax!) Time Machine... very nicely executed. Mail... great improvements I'm still trying to decide which other features make this a must-upgrade. Heck, Time Machine was worth the $109 by itself. Anything beyond that is a bonus.