This game is a few years old now, but IMO it is one of the best RTS games ever made.
It has such a great replay value, as well as being able to play online
Command And Conquer Generals
Command Your General - Select from nine powerful Generals, each with special strengths and a unique vehicle unit. Direct the NATO Tank General to smother the opposition with raw power or let loose the Chinese Secret Police General to spot and capture hidden enemies.
Three Ways to Dominate - Command one of three unique armies inspired by real-world ideologies: the high-tech US force, the swarming Chinese war machine, or the resourceful Global Liberation Army.
Modern High-Tech Warfare - Unleash your fury using modern and near-future military weaponry on the bleeding-edge of technology. Wage real-time war in more ways than ever before, with thrilling air-to-air duels, urban combat, and an enhanced veterancy model.
State-of-the-art 'SAGE' Engine - Experience Command & Conquer in unprecedented detail as you battle it out in full 3D on urban cityscapes, rugged deserts and frozen wastelands. Real-time strategy never looked so sharp.
All-new Units and Tactics - Assemble your war machine with top-secret Aurora Strike Fighters, massive Crusader Battle Tanks, Angry Mobs, skilled Hackers and over 60 other distinct units. Bring death from above with your side's exclusive super weapon - the US 'Daisy Cutter' Bomb, the Chinese Nuclear Missile, or the GLA Scud Storm.
Multiplayer Mayhem - Wreak havoc online, either cooperatively with a friend or go head-to-head in all-out global domination with a multitude of other players.
With 15 new missions, players may be tasked to destroy the U.S. fleet in the Mediterranean, root out a splinter cell in Cairo, infiltrate a U.S. intelligence building, or send in special operatives to capture weapons of mass destruction.
An all-new Generals Challenge mode allows players to control any of 9 new armies in battle against 9 AI generals. The ultimate goal will be to successfully make their way through all 9 enemy Generals, and unlock a select number of their armies for play in Skirmish and Online modes and prove once and for all they are the Ultimate Modern Warfare General.
* 15 new single player missions
* All new Generals Challenge mode allows you to progressively take on 12 generals from across the globe, each with their own strengths, strategies and tactics
* Command one of three unique armies inspired by real-world ideologies: the high-tech US force, the swarming Chinese war machine, or the resourceful Global Liberation Army.
* New hi-tech arsenal of weaponry-from the U.S. Specter Gunship to other next-generation military weapons designed with microwave, laser, and satellite technology-
* Utilize a massive arsenal of new units (e.g. GLA Combat Cycles), new structures (e.g., China Internet Center) and new upgrades (US Hellfire Missiles, and Chemical Suits).
* Battle online either cooperatively with a friend or go head-to-head in all-out global domination with a multitude of other players.
* Collect bragging rights online with all new medals for each enemy General you defeat
* New Combat School feature tracks your stats and provides post-mission analysis-study the feedback to improve your battle strategy
* Rain, snow, and other weather effects further immerse the player in combat
* With more visual enhancements, the most stunning 3D RTS game delivers an even more visceral experience.