This week, I finished a leisurely re-watch of The Maltese Falcon. My feeling (which could change) is that, while Bogart was in more than one film after which was as good, he was never in any better. Sentimentally, I might favor (say) Casablanca, but there I think the consideration is how ultimately sympathetic and likeable Rick's character is. You respect Spade, and feel that at the last he did right; but he comes off as perhaps a little worse for the strife, with an air of damaged goods.
As a footnote, Greenstreet in Casablanca is just something of a jokey distraction, where in Falcon of course he is probably the key player. A pity he probably never makes it to Istanbul.
Elisha Cook, Jr has a more interesting character here in Falcon, than in The Big Sleep (in which he was essentially a walk-on victim), but morally irredeemable: you don't see many things (in cinema of the time) lower than Wilmer kicking Spade in the head after he's fallen down drugged - nor much duller-witted than Wilmer looking back from the door as if he expected the heavily-sedated Spade to stir at all. In The Big Sleep, he was a slight fellow who stood by while others roughed up Marlowe a bit, sure; but if he was not heroic or noble in that, he was guilty of nothing more than a little sturdy sense, probably.