It depends on the person, some girls / guys look better with a type of hair and others look better with a different type. For example, my cousin has a full set of natural curly hair and it suits the way she looks, but when she straightens it, it just doesn't flatter her at all.
So, it varies.
I don't really care about a guy's hair tbh. If I had to pick though, curly seems cute.
Dry, unwashed hair is horrid. I clean my hair every 2 days because washing it everyday kills it. I also change shampoo and conditioner frequently so that my hair stays nourished etc