You guys have pretty much covered all the bases.
I'll just toss in a few extra points I noticed.
1 - Get the game demo via BitTorrent. Nice and fast. And legal.
2 - Command queueing! And implemented quite nicely, to boot! You can queue up a seires of commands by holding down the ALT button for an individual unit/selection group of units, or, you can hit CTRL-Z to jump to queue mode, tell a gazillion different units to do a gazillion different things for the next four years, and then hit CTRL-Z again to watch them all move out simultaneously. Great for planning pincer moves.
3 - Souped-up "box"-select is awesome.
Not only do you have the typical "drag a rectangle" select, but you also can hold down CTRL to get a "draw a curvy-twisty line however you want around only those units you want to select" function! This rocks.
4 - Others have said this already, but I want to reiterate: performance is fabulous. I have a Core 2 Duo E6600 (higher-end of the CPU spectrum, granted), 1GB of DDR400 RAM (average), and... a Radeon 9500 Pro (a midrange card... according to the standards of about 4 YEARS ago!). And yet, I can pump many of the GFX settings up to medium, some even up to full, and still get smooth gameplay. Serious kudos to the coders & optimizers of this engine.
5 - The improved ion cannon literally made my jaw drop (graphically, that is... I am unconvinced that the total destruction it wrought at the end of the prologue mission wasn't a scripted self-destruct of the entire NOD base upon ion cannon impact).
So far, so good - this gets