Warhammer followed by shogun 2. Totally ignoring the setting, warhammer is the most fun simply because of the variety of units and gameplay that each faction brings to the table. There's a lot of replay value. I did love shogun 2, especially for the fortress defense and sea battles, but I think I'd still prefer warhammer for gameplay (which does have some cool fortress defense stuff too, but I did prefer shoguns implementation).