Buu saga Videl definitely. DBS Videl is a shit though.
Videl because she not a slut and has Best Dad.
This Videl > Long hair Videl > Cocoa >>>>> Current Videl
It seems that Gohan is weaker than Piccolo at this point:
>needs Piccolo to train him, meaning Piccolo is at least near his level
>Piccolo fought in the tournament in Gohan's place because Gohan was too weak