Sid Meier's Civilization IV: Warlords [PC]

Did you really need another reason to keep playing Sid Meier's Civilization IV? Probably not, but here's one anyway: Sid Meier's Civilization IV: Warlords. Actually, this expansion is a whole slew of new reasons to keep playing Civilization IV, most of them well worth the $30 you'll spend.

First of all, you get some handy additions to the basic game. There are a couple of new units to make ancient warfare more viable. Triremes can sink pesky enemy galleys, and with trebuchets, cities aren't such impenetrable fortresses anymore. There are a few new wonders to keep the early game more lively: The Great Wall, which runs the length of your borders and shuts out barbarians, is probably the best thing to hit Civilization since the Pyramids. There are also entire new civilizations as well as new leaders with new traits.

The Imperialistic trait is particularly helpful for early expansion. It not only makes it easier to found new cities, but it also makes it easier to conquer someone else's cities by giving you more Great Generals. These new units give your fighting forces a huge advantage, especially if you get them early on. Great Generals spring up regularly for warlike civilizations who might otherwise miss out on the Great Persons that spice up the game so much.

There are also unique buildings for every civilization, which go even further in terms of making the sides play differently. Want to see the Russians really come into their own? See how much their new Research Institutes help with a Space Race victory. But whereas unique units can quickly become obsolete as history marches on (after all, what good is a Roman praetorian in the Medieval Era?), unique buildings tend to be useful throughout a civilization's life.

When you consider how buildings can be used to complement leader traits, some nationalities suddenly seem even more powerful. If you thought England was a financial powerhouse before Warlords, wait till you've tried Elizabeth or Victoria with their brand new Stock Markets. Unique buildings are just the sort of tweak Civilization IV needed to make you want to try every side at least once.