We have a sneezer, too.
The vet says that he has a condition where his palate is too short (or something like that). Anyway, the vet says that he will always be prone to respiratory problems because stuff will get stuck up in his nose just due to the shape of his head. If you look at our avatar, you might be able to see that one of the dogs has a much shorter snout than the other. He's the sneezer.
We were a little troubled by it at first, but we're used to his sneezing now. He had a perpetually runny nose for the first few months we had him, but that seems to have stopped. He also makes this terrific honking noise occasionally, like he's trying to clear his sinuses. It was scary at first, but it doesn't seem to bother him at all. The vet wasn't worried about it, and neither are we.