Yeah I am also an Agatha Christie fan.
And my favourites are Death on the Nile, Murder of Roger ....., Ten Little Niggers, Murder on the Orient Express, Why didnt they ask Evans, Ordeal by innocence to name a few.
About Crooked House, I vaguely remember it as the story with no detective in it. The story unfolds so very slowly with a shocker of ending onto the last page.
Well I am not so sure whether I should mention the story here, but briefly.
People die in and around a family and there are several suspects as usual. But the murders are erratic as if done by some psycho abnormal person - the books builds on you till the ending which is a huge startler.
Not one of the best books but certainly worth a read and a must for an AC fan due to a different kind of narration style.
Cheers