Sins of a Solar Empire, its expansion, Rebellion, Rome: Total War (I know it isn't age of mythology, but it's still a stellar RTS.), if you can find a copy LOTR: Battle for Middle Earth 2, Company of Heroes, and Warcraft 2. --- TBWNN i5 3570K @ 3.4Ghz | GTX 670 | 8GB RAM
Command and Conquer Tiberian Sun + Firestorm, Red alert (hasn't aged as well as the others though) Red alert 2 + yuris revenge, Command and Conquer Generals + zero hour, Command and conquer 3 + kanes wrath, and if you enjoyed the older Red alert games then the 3rd one is worth picking up, I personally didn't like it much though.
Stay away from the browser game and C&C 4
Also check out the Stronghold series (crusaders and stronghold 2 are considered the best of the bunch by many) its abit less focus on combat because you have to deal with managing a medieval castle/village but combat is still the focus.