Good thread, this is something I have always wanted to attempt... For me it would go
JFK-LAX UAL 752PS F
LAX-SYD QAF A380 F
SYD-SIN SIN A380 F
SIN-DXB EK A380 F
Depending on my mood
DXB-LHR EK 773ER F
LHR-JFK BA 744 F
or
DXB-JFK EK A380 F
That would be quite the fun trip, I could knock out all of the A380 routes in one go!