Only one cereal? None of the above. Quaker Oatmeal Squares. Easy to eat without milk if I want, no gluten/wheat so I don't get sick from them, and I like the taste.
That... that looks like Chex, from General Mills. You might be able to get coco Chex in the states? General Mills and Nestle are owned by the same parent company, they might be close enough, taste-wise.
Do you have to choose from those 8? Because I have eaten Weetabix for most of my life and wouldn't trade it for any other. Mainly because I find milk on its own revolting and Weetabix soaks it all up so that I don't have to taste it as-is, which none of these other cereals do. Talking of which: Seeing that you're a fan of chocolate cereals, try spicing up your Weetabix a bit by sprinkling some drinking chocolate over it, that's what I do and it gives it some much-needed flavour. What are you smoking? Cereals give a great amount of fibre and carbohydrates, both very important for one's health, with no fat or cholesterol or anything like that. I can't see how it could be perceived as unhealthy when up against a lot of other breakfast options (fry-ups, e.t.c) But then what some of these crackpot 'food scientists' call 'healthy' changes every fortnight. In the past such nutters have claimed that eggs, potatoes and bread have all been unhealthy, which of course is complete rubbish.
I do have a special concoction. Weetabix + baking cocoa powder + sugar + coffee. Let me tell you, it is absolutely delightful! But, I recently cut it out (at least for the time being) to eliminate those sugary calories. Most cereals are absolutely terrible for your health. Many of them are pretty much the equivalent of candy in milk. There are some exceptions, like your aforementioned Weetabix (or All-Bran, Shredded Wheat or the like.), but most are lousy in terms of healthy eating. In nearly all instances you'd be much better off eating some plain oatmeal with some fresh fruit sprinkled in.