There isn't a lot that SL can do that Leopard can't do when it comes to the end-user experience.
like support for PPC's
I don't have any left but a $3000 PC (dual G5's etc...a couple of years ago) should have a long support cycle imo.
wasnt PPC (G5?) the first desktop mainstream chipp to have 64bit extensions? its kind of a shame to see them be a waste