I have a Henckels 220/400 waterstone, which is hard hard hard and I mainly use for flattening my J-stones or repairing chips.
The stones I actually use are:
1K King (I thinks its 1K, it might be 800 or 1200 but I no longer have the box)
3K King
6K Shun (well Shun branded, not sure who makes it...