I am currently enjoying Paul Johnson’s Churchill very much. I’d always admired Churchill, but getting to know him better makes him all the more likeable to me.
I like Churchill a lot though I realize that he had his failings. I recommend reading Hastings’ “Winston’ War” since it really does look at both sides of Churchill. I also would recommend reading “Partners in Command” by Perry if you want to get some insight in the interactions between Churchill, Marshall, and Eisenhower. You can really see that Churchill’s powers of personality which worked so well on Roosevelt had very little effect on Ike and Marshall.