Grab Advance Wars: Days of Ruin for $17.98 (save $12).  It is the Amazon Deal of the Day for Tuesday, October 21, 2008.

This scored an A- on 1up.com.

Check it out:  Amazon Deal of the Day

Product Description
Almost 90% of mankind has been killed off following a devastating meteor strike that has caused a massive dust cloud to blot out the sun. Scattered survivors pick through the wreckage, and the remnants of several military superpowers patrol the ravaged landscape, some factions protecting the innocent while the others prey upon them. The two rival world superpowers, Rubinelle and Lazuria, continue to fight among the ruins of their countries, the few surviving military leaders of each side carrying on the conflict begun before the catastrophe. In their wake, various warlords rise to power, seizing scarce food rations from the defenseless survivors and attempting to assert their dominance in the absence of law and order. Follow the Rubinelle COs Will, Brenner, and Lin as they embark on a mission to rescue as many of the survivors as possible, with the help of the mysterious Isabella, an amnesiac girl who seems to know vital military secrets, and various other sympathetic factions.