*ponders* well, the platinum edition (with DoW, DC, and WA) runs for 'bout $30 now... and Soulstorm is $40... if you sell off your original DoW, then the cost is only as much as an A-list console game.

(and after checking the box, yeah, I'm pretty sure you need DoW for WA, but not for DC [but I could be, and probably am, wrong])