Firstly, I'm going to assume that by 'sex sells' you're referring to the use of sexualised (e.g. through sexy poses, clothing) females or males with little or no relevance to the product, to sell a product.
How about any industry where females make up a large part of your customer base? I think it is pretty hard to argue that, say, the iPhone would be more successful if it's marketing department decided that it would be better to use the idea that "sex sells" to sell their product compared to the type of marketing that it actually uses.
"Sex sells" is never tasteful nor respectful: it's only useful when you're selling your product to a sexist audience. (Obviously this doesn't apply if you're selling sex toys, porn, body image, etc.)
