there is none.... digital version by all means should be cheaper. i mean theres no medium, no packaging, or transport.  thats at least $10 right.  they can't suggest they're paying for bandwidth to download.  if they are i suggest they get hostgator accounts  lol. 

Maybe that helps? (Not claiming this is 100% correct, feel free to prove me wrong if you've got other numbers).

Download games are expensive because of the industry's dependency on retailers. If they sold their digital copies for half the price retailers wouldn't sell any games and therefore stop selling gaming related stuff. Hardware manufacturers need retailers though - because of hardware sales. They can sell their games digitally but not their hardware therefore retailers are needed. (Of course the other stuff that's been said is correct as well - but this is a major point too and shouldn't be underestimated). 

I always thought it was something to do with bulk ordering.  When you buy in bulk (1000s of the same product) you will be given a discount in most businesses (wholesale price) compared to the singular purchase.

As this isn't done with digital copies - only 1 version is required to distribute to everyone - there's not as much margin for price reduction.  In a lot of cases you may even find that at launch a physical copy can be as much as $10 less than the digital ones.

As we move progressively to a digital distribution world specialist video game retailers will become less and less relevant. Consoles will be sold through online stores and general appliance and department stores. So there's really not much need to appease retailers by keeping the price of e-copys of games down. general retailers will sell consoles by themselves and make a modest profit margin on them. But consoles will be one small part of their business and they won;t care a bit about software.

It's not price fixing and it's not illegal.  Many manufactures sell their own products, but keep their prices at the msrp (manufacture suggested retail price), because if they undersold the retailers that sold their products, they wouldn't have any retailer carrying their products anymore.  This is true in almost all industries.  

Now, as to why digital prices stay higher longer, that is also because the manufacture (or publisher in this case) hasn't lowered the msrp, but some retailers have excess inventory, so they lower the price to try and move them.

As for why games are $60, that's the price that most of them have settled on.  It takes many things into account, but doesn't benefit all publisher the same.  I see people complain that $60 is too much for a game, and for some games it is, but I paid $35.00 for Pac-Man on the Atari 2600 and $179.99 for League Bowling on the Neo Geo AES  when they first came out....$60.00 for a lot of the games out now isn't bad at all in comparison.

other than the digital copy at $45 would be competing with the retail copy at $65 and would anger many retailers.  I think that a solution for this would be to offer digital for $10 less than physical, and let the retailers sell game download cards.  That way, people who don't need to have that physical copy could save some money and the retailers would still make their money.  As for me, I'll never spend more than $20.00 for a game that I don't own or can't resell on my own.

If I can sell a painting for $60, I would.
If I can sell a picture of a painting for $60, I would. Then stop selling the painting altogether.
Who's the sucker? You, silly.

Vote with your monies.

Because things are not priced according to

x*C

where x is some constant and C is cost to produce,

Nor are they priced according to x+C.

They are priced according to how much people are willing to pay.

I really think this has got to do with the retailers as the digital versions are eating away their turnover. I don't see many friends buy retail versions anymore for PS vita games as they are slightly cheaper digitally (when they first release) and the effect is, that it's now days even hard to find some games at retailers. So I can imagine that if this happens in the same way with PS3/XBOX360 games the game stores will be empty very rapidly.

But with this I come to another questions: Why do we see lower priced XBOX360/PS3 games at retailers, but Nintendo games don't get any price reductions.

I think I need some more explanation :P