Universe at War: Earth Assault (RTS, Petroglyph games).
Pros:
Wonderfully a-symmetric
Surprisingly well-balanced
Interesting use of Hero units and tech trees
Music by Frank Klepacki (oh come on, how is that not important?)
Cons (and why it failed):
Games for Windows Live
Bad/borderline useless hotkey and interface design
Not-the-greatest pathfinding, unit responsiveness, etc. Playing the game feels like driving a tractor.
Somewhat hard to learn
Almost nobody has heard of it, so noone plays the multiplayer.
Pick it up from Amazon for $1.13, new. Or $0.10 used. Now that's a bargain.
On another note: The problem I had with Mirror's Edge was that it wasn't open-world enough. I have good enough memory to remember exactly where to go after the first time I played it, so there's no replay value at all (for me. I have that same "problem" with all kinds of remotely linear games). Also, after having played ME, I cannot understand how people think 3rd person platforming is better. I actually find 3rd person much harder... Really.