I downloaded the iPhone SDK last night (once the site wasn't swamped). It looks pretty cool so far, and it's a good excuse to actually use Objective-C after using Ruby and C# professionally for the past couple of years (Notwithstanding all the proprietary stuff I had to use at Hewitt Associates)
Xcode's gotten leaps and bounds better in the past couple of years. I definitely applaud the tools team at Apple for the hard work. However, one thing that's a little bit disappointing is the version control systems that Apple integrates with Xcode: Subversion, CVS, and Perforce.
I think it would be a huge boon if they could add in Git (and, oh what the heck, Mercurial) so that coders can use their favorite VCSs in xcode.
Ok, I think I can manage by using git with the command line at the xcode project structure, but where's the fun in that? Who really likes context switching these days?
Apple, please integrate git and mercurial into Xcode by the WWDC, at least.