Golf is key to a number of books by Agatha Christie (not only in the Poirot series -- Hastings is not the only character by Christie who is an ardent golfer). So my list of favorites is largely a mash-up of BrokenTune's and Obsidian's:
Agatha Christie favorites:
1. 4:50 From Paddington
2. Murder on the Links
3. Why Didn't They Ask Evans?
Honorable mentions from my TBR:
1. P.G. Wodehouse: The Clicking of Cuthbert (short stories)
2. Ian Fleming: Goldfinger (I've seen the movie but have yet to read the book)
... and a few Christie short stories:
1. Murder in the Mews (Poirot)
2. The Mystery of the Blue Jar (standalone)
3. The Sunningdale Mystery (Tommy & Tuppence)