I have a Dell Latitude with Rage Mobility, etc.
Had a great deal of trouble with the beta demo (no cursor, etc) but am running gold demo at 1000 something x 700 something (top resolution for my display) with no trouble.
Smoke: "Transparent" smoke looks exactly the same as "Fast and compatible" smoke, except bigger.
Buildings: In default setup, there is no transparency. If I toggle hot key to "transparency off" then the walls disappear on the occupied floor. So I guess, no building wall transparency.
Not cool overall, but definitely playable and all things considered, I'm happy.