I have three "King" stones. They're about 25 years old and the markings are long gone, but I believe they're 2000, 8000, and 12000. They're dished, chipped, and in some places cracked, but they've seen their share of woodworking chisels. I don;t use them anymore, in favor of plate glass and wet/dry paper of various grits.

These days, I think diamonds are the way to go. DMT 8" series will be my choice if I ever decide to buy benchstones again. Probably XX Coarse, Coarse, and fine.

If you get waterstones, you should also buy a small Igloo (that's what I've been using all these years) or other "Tupperware-type" container to keep them in. They should remain immersed in water so they're completely saturated and ready to use.

ON EDIT: I saw Izzy's post and they are (or were) very expensive. Japanese stones are very soft and easy to dish, but they're also easy to flatten with another stone or some plate glass and compound or wet/dry. Their cost is another reason I like diamonds. Despite the hype and lauding they'll often receive in write-ups, don;t be fooled. In the end, they're just stones. If you think about it, we often elevate foreign products - food recipes, clothing, cars, and other things - to a mystical level, simply because they're exotic and different from what we're used to. Japanese waterstones are good, they sharpen metal objects, but don;t expect them to be anything more than what they are. Consider that when weighing their value against price.