Anno. The newest 2 even have good graphics.
Age of Empires (even if the third and the second are really shit)
Command and Conquer (the newer ones are shit too...)
Battle for Wesnoth is awesome, but it has really poor graphics
My favorite are:
1. Age Of Empires (all versions)
2. Rise Of Nations (all versions)
3. Cossacks (all versions)
Edit:
Also star craft is good game, but I didn't play it much.
I play it since 2009 and it's a great strategy game, in my oppinion of course. It's a good-looking and very long game. You start in year 1400 and finish in 1815. One second means 1 minute, so it's gonna take a long time (you can speed up the game anyway). You start with a simple dynasty and have to make it greater and defeat your opponents.
I recommend this to you, as planning to make the game popular again and have a decent play with others.
Of course it does. No sarcasm.
I play it more than III due to the gameplay, it's way better with the unit strategy stuff like guarding, square-like defense for other units... and i personally love the medieval age, plus hate the imperial one.