I recommend "Guard Dog Moly 525" grease. Guard Dog is a VRCC sponsor too!
A Honda Certified Gold Wing Technician I know uses "Belray Assembly Lube" (with Moly) exclusively.
Some members also use Belray Waterproof Grease" with good results.
Don't forget to replace all three O-rings whenever you service your drive unit.
+1 on the GD-525 on the rear wheel splines, pinion cup and drive shaft. I have also used Lucas water proof green grease on the shaft splines with good luck. But then again I look at all the drive splines every spring regardless of the miles.