Total Annihilation is probably one of the best RTS games. While it is quite old now, the huge amount of units and the activity of the modding community made it quite a cool game with endless possibilities. Using a innovative (for its time) 3D engine, you could have robots fighting on the ground, in the air, and on the oceans. While its single player was not strong or as polished as Starcraft, I felt it provided a lot more to the player than the stale Starcraft tactics. Red Alert is still one of my favorites. The gameplay and story was fantasic.. and I'm always a favorite of Fullmotion video cutscenes (FMV). Red Alert 2 and its addon were quite fun to play. Superweapons made multiple player sorta cheesy, but it was still fun. I also recommend Homeworld and its sequel Homeworld 2. It's a strategy game taken to 3D space. It is quite fun and the graphics are just awesome. Relic, having done Homeworld and working on Company of Heroes, also did a strategy game Dawn of War. It is quite good (though the single player was short for me) - based in the world of Warhammer 40K So none of those are technically really 'World War 2' games. But there are a lot of good strategy games if you're willing to go outside a specific genre. How many times can you revisit the same WW2 events anyway?