Completely with you on The Maltese Falcon and The Big Sleep. I'm not really a fan of The Narrow Margin, either. I love In A Lonely Place, Double Indemnity, Niagara (if you count that), Sweet Smell of Success, The Naked City, Cape Fear, the underrated Murder By Contract, Blast of Silence, etc. Still tons I need to see. It's the one genre I keep coming back to when I feel I've exhausted other avenues.
Also, I'll take Mitchum over Bogart any day.