The three map packs can all be had for 50% off, or $5 apiece. The sale--which also coincides with a double-XP bonus--runs through next Sunday.
I thought about getting this because my friend raves about how Nazi Zombies is so great online.. Well even with this sale, I still deem it pointless to buy it so close to Modern Warfare 2's release. Especially since the price is still so high. There's so many games out right now and coming out it's complete nonsense to buy it now unless you already have it.