I suppose it depends on the game. Considering that COD has a released title every year, is it really worth $60 for the slight improvements which could have been an expansion? In my experiences so far with MW, MW2 and the current one: no.
However there are other games which have much more reasonable pricing, and typically I also find them on STEAM.
as a FYI, Bioshock 2 is $10 right now on STEAM.
There's also plenty of Indie games on there for very reasonable prices, as well as old classics that actually work in newer OS'.