I'm with you on the 7th-Cavalry-Robot-with-swivel-chair-castor-wheels being the coolest (nice description by the way!). The composition is the most dynamic, the Japanese script always does it for me AND it's got missiles!! However, your wife has chosen the winning personality of Mechanical-Walking-Robot-With-Spark over the others and I'm with her on that - I can marvel at castor boy but I can't love him! I guess it must be a gender thing?
I also can't help but admire the world of the Maxell 'Gentleman's Club' - spiffing.