I cannot believe I did not include anything from the Battletech games. I love the Mechwarrior series most of all. It's complex yet exciting, with half the game being about mastering the mech itself, becoming master of your machine.
Mechcommander is also fantastic with some of the most intense battles I have ever had. Never before and never since have I shouted encouragement to one of my little guys, though it was during a demo of Mechcommander but i still think that counts.
That said, I dont like the Mechassault series. It's too detached from the Battletech ideals of complexity and realism in a fantastical and explosive setting.
Also once i got reading into the history, I love the thousand years of war and peace, migration and return, all starting from the real-world mid 1980s when Battletech was first made.