@JakeHoffman:
Senji gets a few seconds in to the sniffing process and then snaps into aggression, he is a lot better if they can have that moment and then go play.
My Perry is like that. His idea of "greeting" is to try to nip (or bite!) the other dog in the face! If you can get past that initial reaction, and if the other party is female, then things are fine. He met his match in my girlfriend's Jack Russell bitch, who put him in his place in 10 seconds flat. But mostly we don't see a lot of other dogs, and I have no plans to take him to dog parks and the like, so it is a non issue for me, other than to pay attention when we are out walking.
If I needed him to be more social, I would take the time to try to sort this out, but there aren't a lot of opportunities to interact with other dogs where I live.