[quote name='o2012o']Diablo 2 still costs that much because it is
A) still a great game
B) still played (a lot) online[/QUOTE]
If there is one company whose games tend to hold their value for very long periods of time, its Blizzard.
Starcraft is, what, an 12 year old game? And its MSRP is 20. WC3's MSRP is 30 or 40 (the battle chests, of course)
Don't forget, those who are buying things today in the blizzard sale, you can register your CDKEYs with a Battle.net account and have them saved as Digital downloads for the future!