SpellForce 2 Dragon Storm & Shadow Wars for US$14.99 through Steam. The games are usually $19.99 each - so you save >50% on buying the games individually.
You can also buy as a gift through Steam (just select the option on checkout) so it could make a good Christmas present.
Not sure when this offer expires - sorry.
Weekend deal. Finishes Monday afternoon our time or thereabouts.
Game looks really crap though.