Math notation uses := for assignment and = for equality, no? So in that sense Algol and the Pascal family are more consistent with that, while C actually diverged.
Depends on your field. Some math subjects would argue that "assignment" does not exist, because the same name within the same scope always refers to the same value, whether it's known or not.
Within algorithms, I'm most used to "<-" for assignment, for example "i <- i + 1" inside a loop to count iterations.