For me, my "favorite" moment would have to be my longest memory to the character, when he yelled out, "This one's for you, Morph," before destroying a Sentinel in the X-Men animated series that used to come on Fox. It might not be iconic, but it stayed with me as a kid whom was nearing the exit point of adolescence.
Truthfully, it all depends upon which version is being compared... Base level: Flash is faster than Sonic Mixed level: SuperSonic is faster than Flash Ultimate level: Godspeed is faster than SuperSonic