Corn snake without a doubt is what you need to get, the other three you listed are not good beginner snakes especially the milk snakes.Corn snakes are the best snakes you could get for your first snake, and they are addiction.
I would get a Under Tank heater instead of the light though. Besides that everything you said seems to be right.
Check out the Corn snake forum and that will be alot of help to you.
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Cameron

