Definitely one of my favorite RTS games.
The Company of Heroes series offers many great campaigns to enjoy, different factions and a true to history feeling.
The Squad-based strategies are easy to get into yet are challenging to use correctly.
Upgrading and equipping your troops with specialised weapons is an essential part of the game, and the balance is nicely achieved; you can counter the biggest tank rushes if you use the right units, use cover or hide in buildings.

Great franchise, amazing value!