I just wanted to give my two cents on the thread title. MMO is the way to go with pretty much every game genre. it makes games more challenging, because "ai" will never be as unpredictable and interactive as actual intelligent life. thus MMOs are a fantastic concept. a MMORTS sounds amazing! now all I need is a realistic war-themed MMOFPS, with ninety-thousand men firing at will.
I still enjoy a good single player game though, since they are easier to pick up and play, without depending on anything but the game.
consequently I like that DoF will have both an on-line and an off-line mode. *a lot*. :-)