Halo Wars will sell better than Killzone 2 - at least initially.
Pre-order at my local gamestop for Halo Wars is at 75 - 100 preorders at this store is considered a megahit game qualified to have a midnight launch. So this is huge for Halo Wars.
He also checked his computer for me to see other local Gamestop/EB game stores and pre-orders for Halo Wars doubles pre-orders for Killzone 2.
I think Halo Wars will be a huge success - especially for its genre.
I'm not sold on the game yet - not planning to purchase it but I have to admit that I'm getting excited for this game.