A good strategy game to buy during the steam sale?

Besides all the Paradox stuff, I suggest Frozen Synapse.

It's really really really really fun.

Frozen Synapse... done deal.

CHILDREN OF THE NILE

C'mon. :D

(No, in case anyone's wondering, I have no association with Tilted Mill, the CotN devs.)

Oh damn!! GET COMPANY OF HEROES

Greed Corp?

Civ5, CoH, Total War series, Settlers series, Stronghold Collection

I remember enjoying the Europa Universalis series. It's a grand-scale strategy game, unlike Age of Empires and such, which focus more on battles than managing an empire. It really depends on what kind of strategy you like.

Buy warcraft 1,2,3 and Starcraft 1,2..you wont find better strategy games :) (not in steam)

Binding of isaac totally. I am playing like crazy, just won one copy :D