#39 Use XIB for development
In Xcode 3.0, Apple introduced a new Interface Builder file known as xib. This file, unlike the nibs, was one file and was in an XML format, making it friendlier with different repository formats and diff utilities. Also, by default, when you compile the application, it also "compiles" the xib into a flat nib that the application can use. In Xcode 3.2, when building an application, it automatically "strips" directory nibs into a flat nib. The flat nibs cannot be opened by Interface Builder.
After all that rambling, I'm just asking to move all the nibs to xibs. It's not hard to do, and would make modifying them easier, especially in regards to CVS (I had an issue where I changed a setting in Interface Builder which created a file and removed another within the nib. When I updated the cvs repository, cvs put the missing files back)