Depends, really. If I need to write rapid fire or the words are just coming that fast, I was last tested at 88 WPM without error. I don't know how fast I can go if you count in an occasional typo or two. It also depends on what I'm typing. If it has tricky keys, I'll have to slow down, but if I'm not having to do much with the far sides of the bottom row, then I'm usually good.
Migraines slow me down and make me write gibberish even I can't figure out later on. =p
It always surprises me when I meet people who can't type without looking -- it trips me up, but some of the people I've met can't type for crap if they don't. When I was a kid, I loved to write, and got a hand-me-down laptop from, like, 97 or older. It had no internet and there was only one extra program on it: Mariam Webster's Typing. It played Beethoven's 9th in digital beeps whenever you made a typo (and over one another if you made multiple mistakes), so you learned the basics quick. ._.