Darned if You Do by Monica Ferris: the latest but one of the Crewel World series, this novel had some sloppy editing, but it was made up by a genuinely interesting mystery. Ferris's character development continues to shine.
Rose Cottage by Mary Stewart: A quiet, gentle story set in post-war England, this novel is part mystery, part family drama, and part romance, but is mostly a pleasant diversion.
The Strawberry Hearts Diner by Carolyn Brown: This was ... kind of awful. I'm all for cozy novels set in cute small towns, but this was too unrealistic. The small-town superiority was too ridiculous, the characters' relationships developed far too quickly, the alleged conflicts were too minor (or just petered out instead of being resolved). I ended up skimming through to the anti-climactic ending, and it wasn't worth it.
The Mystery of the Yellow Room by Gaston Leroux: Published in 1907, it's one of the first locked room mysteries, and well constructed; I was able to accurately guess the perpetrator of the crime and his motive, but the way he did it confounded me. It's also a product of its time; the success of the crime hinged in part on two people deliberately impeding the investigation to protect someone's honor -- not an internal sense of honor that comes from integrity, but an external one based on reputation. I have little patience for that sort of thing, and it kept me from appreciating the novel as much as I should have.