As a software engineer, I spend most of my day typing code; so typing using intellisense can be really, really fast, however due to the nature of that, its very rare that I type large quantities of words in a go. A quick typing test would suggest I type at somewhere between 90-100 WPM. I could probably get a higher number if I didn't care for accuracy. In saying that; its very rare that one types that fast under any circumstances unless specifically doing it for professional reasons. (Typist, transcriber, etc) Typing 20-40 WPM is more than enough for anybody, given that when we are writing things up for school/work/personal reasons, typically we don't just spew words out as fast as we can type; usually there is thought put into it. Hence, 20-40 WPM is a great typing speed for anybody.
