Hmm, I was wrong about Halo Wars beating Killzone 2 first week.
I suppose the limits of an RTS on consoles overcame the popularity of Halo. I tried the demo at a friend's house, it was good fun.
Now, how long before the people who said "Halo Wars will destroy KZ2 in sales" switch to "Lol, the most hyped game of this generation [lol] only outsold a console RTS by 250k first week! PS3 is teh doomedz!"