Act of Aggression [official site] is shaping up to be one of the finest traditional base-building RTS games in a good while. I've written about why that might be already but the short version is that Eugen, developers of the Wargame series, are returning to and building on the template of their Act of War games. That means near-future military combat with smart strategic thinking and beautiful model-like units. Two of the three factions have been outlined in video form and you can see them below.
First up, the rigid but mighty US Army.
And here's the Chimera, adaptable but lacking some of the high-level specialism of their opponents.
A video for The Cartel is coming soon. Expect units that hit hard but crumble quickly. And railgun turrets.