For me, it depends on the series. A Dresden Files book is worth the pre-order price so I can read it on the day of release. Just like some movies I want to see on the day of theater release, in 3-D. I expect it's going to be worth the price.
Not a lot of authors will get first release price from me. If I feel its' too much, I'll wait. I have several books already on sites that will email me if the prices drop, and an Amazon Wish List entitled "Too Expensive". I'll peek at it once in a while to see if prices have dropped.
I don't care what the other formats cost. Not for that or any other book for that matter. I just care if it's a price I want to pay in the format of my choice. Odds are I'm not going to buy it in the other paper formats anyway, even if they're practically free.
Don't have the space.