I generally also just say "bless you". It occurs to me, though, that given how many other cultures use the same words they would in raising a glass for a toast, such as the aforementioned "salud", and the Polish "na zdrovie" (to your health!), maybe it would be appropriate to just use "cheers!".
Do they say that in England? I lived there as a kid, and have visited back a few times, but although I know "cheers" is used in response to any number of situations, I don't recall, offhand, whether a sneeze was one of them.