Great interview of Fred Brooks in the August 2010 Wired magazine (sorry, no link at this time).
The critical thing about the design process is to identify your scarcest resource. Despite what you think that very often is not money. For example, in a NASA moon shot, money is abundant but lightness is scare; every ounce of weight requires tons of material below. On the design of a beach vacation home, the limitation may be your ocean-front footage. You have to make sure your whole team understands what the scarce resource you’re optimizing.
"Your #1 competitor starting out will always be the BACK button, nothing else."
— Gary Tan
The recent update to iBooks added PDF support. Unfortunately, the reading experience is no where near as good as the epub experience.
This was a bummer for me since I own quite a few eBooks in PDF format (and converting them to epub does not yield better results).
Thankfully, a tweet from John Grubber lead me to SimplyPDF which makes the PDF experience much more tolerable by allowing you to focus on a particular area of the page.
Here are too screen shots to compare:
The Default View in SimplyPDF

The Focused View in SimplyPDF

While it is no way near as good as a epub in iBooks or mobi in the Kindle app, it does get the job done for now.
A great line from Design Patterns in Ruby by Russ Olsen in talking about You Ain’t Gonna Need It (YAGNI):
Barring a sharp blow to the head, as you stand here today you are as dumb as you ever will be.
You get smarter every day. Your users (generally) understand your app and their needs better every day. Unnecessarily trying to solve future problems is really just guessing, so why do it if you do not have to?