I have every one of the 100+ books she published and have enjoyed rereading them over the years (I'm blessed with forgetting the ending of books). Nothing does justice like reading the actual books though, as the mind is way more powerful of conjuring up the imagery than any movie or TV series. Even if you have only seen the acclaimed David Suchet series you should still try reading some of the books.
Some of the best to read are: Murder on the Orient Express, The Murder of Richard Ackroyd, And Then There Were None, The ABC Murders, The Mysterious Affair At Styles, Murder At The Vicarage, and of course the longest running play The Mousetrap.
There is good reason why she was known as the Queen of Crime.
Watch at New: Agatha & Poirot Partners in Crime Episode 1 Easter Bank Holiday Monday 5th April 2021