I think historically/traditionally, English Breakfast is Keemun, but most of the modern ones on the markets are blends and, in my opinion, are quite different from the Keemun-only English Breakfasts. I think the modern ones are a bit stronger / edgier.
But Keemun might be a great choice if you want a black tea that is a little mellower.
Another that you might want to look into, if you like lighter teas, is Darjeeling, although the aroma / overall qualities of that tea are also very different.
It's been my experience that when you pay more for tea (assuming you're buying from a reputable company), you tend to get smoother teas...so it might be worth shelling out a little bit more for something premium. I.e. a Yunnan Gold tea vs. a regular Yunnan black tea...they tend to be a bit smoother. I recommend trying a bunch of samples of different black teas, and seeing for yourself what you like! You're probably going to discover some teas you end up liking a lot more than the tea bags you were using before!