@pastanaga - They really are completely different crops though. Sweet corn is mostly grown so that people can eat it fresh. You can eat maize fresh as well (cooking it over coals can be delicious) but it's mostly grown to be used for other reasons.
I don't think you can make sweet corn into popcorn, for example, or dry it and grind it up for flour.
I do think you might be forced to choose one or the other though, since they are both varieties of zea mays and so they would probably cross pollinate if planted together. If you are intending to collect your own seed, planting them in the same area, where they would contaminate each other would be a mistake.