Just in case you didn’t get the memo, you can get Left 4 Dead 2 half off at amazon.
Since it’s basically an update to Left 4 Dead 1 (which is to say it doesn’t bring anything new to the table), it’s now appropriately priced. Also since you’re buying brand new, you get the code for the extras.
If you’re into co-op gaming, left 4 dead in general or simply looking for a scary game, this is it. Left 4 dead 1 was good until they tweaked the balance, at least this time I’ll be joining in late enough I won’t know. Four levels for $35 might be a bit steep, but with too many modern shooters out there, I think this is a much better buy than Bad Company 2.