Final Fantasy games definitely qualify. The only "dud" has been FF14, as every other entry has had immense praise (and it's fair share of criticism as is to be expected when you have a huge franchise), and high scores.
12 and 13 both have noticeably lower scores on sites where anyone can submit a score. Metacritic or here for example. Whether a 77% average means the series isn't "consistently good" anymore I'm not sure. But there's no doubt 12 and 13 have received a lot more criticism than anything since the series got really good around 4.
--
http://www.youtube.com/watch?v=npHDxSvwCE0