Defense Grid - The Awakening
Rome Total War with all expansions
Medieval Total War with Kingdoms
The Infinite War Battle Pack for Supreme Commander 2
X3 Albion Prelude (with cumulative discount I think, because I also own Terran Conflict)
The Total War games I got mostly for the Europa Barbarorum Mod, since I can satisfy my needs for historical play with the Paradox titles I own (Rome Gold, EU3+all expansions and Victoria + AHD).
I was tempted by Warlock - Master of the Arcane, but I'll invest my money in Fallen Enchantress, it'll sure be the best fantasy 4X out there.
Some of the best games I already own and others are just not my type, like The Witcher... meh. I love Skyrim though Still... a sale is always welcomed.