I started to begin a list, but then I realized that I won't necessarily reflexively buy any book. There are those I'm pretty likely (say, 90%) to buy, but even authors I know I enjoy I look over the books to make sure the premise is interesting to me before I fully decide to buy them. I'd still keep
Anne McCaffrey (non-collaborations, I mean) on my "most likely" list, but she doesn't seem to be writing much these days -- I don't mean to imply that the Lady hasn't earned whatever rest she cares to take! Collaborations, which lately seems to mean "mostly written by the 'collaborator'" definitely get looked at, but I wouldn't say I'm more likely than not to buy them.