I'm no nutritionist, biologist, biochemist, or doctor. But I can tell you what Ive heard and learned over the years.
Coffee itself isn't inherently bad for you. Some science suggests its good for you in fact. The problem is in how we choose to prepare it for drinking.
Sugar and cream... both up for debate I think. Sugar is an essential component to life. Milk isn't bad for you either, necessarily. Like anything else though, moderation is key. Milk does contain fats and sugars. So if you're watching your intake of these things for health sake, then milk contributes its own parts. Aside from that, unless you're lactose intolerant, milk is a-okay to consume.
I like lattes too but you need to use espresso for that. Your instant coffee version doesn't sound particularly appetizing to me.
I find that whenever I use straight milk in regular coffee, I don't know if its the heat or the acids of the coffee working on the milk, but I get this sour taste after twenty minutes or so. I don't get that flavor with other creamers, even dairy-based creamers. I've started using those flavored Carnation-brand creamers because of it. Oddly, I also don't get that sour flavor when I use straight milk and espresso.