As a newbie XCode developer I would like to know what tools you use to support the XCode development experience (e.g. for iPhone development).
For example, DOxygen for code documentation generation.
I'm also keen to know what you do to make all these different tools work in a cohesive fashion.
Mercurial to source-control things
Bitbucket to host that source and provide issue tracking
Dropbox to make the source is both sync'ed and backed up
Doxygen to document things
Textmate to hack on code quickly without opening up XCode
VectorDesigner to produce vector graphics
Omnigraffle to produce any pretty diagrams that may be needed
A PAPER notebook to jot down notes
And because I do iPhone development - App Annie to track how my apps are doing
OmniGraffle for the few diagrams that have to stay around, a whiteboard for almost all diagrams.
Trac for issue tracking, I've slightly used the wiki too.
CC.rb for continuous integration.
An alternative editor! Especially if you use alternative languages in parts of your project build processes. XCode is terrible for Python development especially if code comes from a third party. To that end it is a toss up between Aquamacs and Eclipse with Pydev.
XCode has a huge number of problems outside of Python too. Between bugs and unexpected behaviours it is very unstable in my opinion. Still it is the best way to go about building Mac and iPhone projects.
One thing I've just come across is a "thing" (service?) called MacPorts. This seems to open up a lot of opportunities for gaining access to other tools that may be useful. For example, ImageMagick - a command line tool for image manipulation (e.g. tiling.)