First of all, I am shocked that this character has yet to be acknowledged:
Scooby Doo is probably THE KING of animated sneezes and is very likely the whole reason many of us even know about our fetish! I remember memorizing the episodes' titles so that I always knew which ones included sneezing. Large nose, great build-ups, explosive finish, inappropriate timing...I could go on and on about this dog for hours!
Yes, I think that Scooby's nose is AWESOME - very big and very sensitive! And I think that it would be even better, if his nostrils were more visible (And if they were already visible, then in my opinion they should also be really big)!