Just cause I picked the obvious one, doesn't mean I'm not interested in the others
It's hard not to appreciate the sheer scale and drama of the 2nd Battle of the Atlantic, and that's what I think keeps people coming back to it. I hope interest in it never dies away. Ironically it's not nearly actually as important, strategically interesting or close-run as some people make it out to be. It was a pretty basic war of attrition that one side lost before it even started. The devil is in the details though, and the absolutely mad effort that the Germans put into that desperate struggle really makes for a Wagnerian sort of epic, and that's the sort of stuff that memorable stories are made of.
At the same time, I think there's a lot of fascinating stories from other theaters and eras too. I think people often underestimate just how hard the US submarines fought in the Pacific, for example.