This is how I set up development machines sometimes.

do_these_things

1.	Xcode
2.	xcode command line tools
3.	git
4.	brew install libksba autoconf automake apple-gcc42 qt imagemagick libxml2 postgres tmux macvim
5.	fix imagemagick library names (see below)
6.	x11
7.	rvm
8.	dotmatrix


cd /usr/local/Cellar/imagemagick/6.8.0-10/lib/
ln -s libMagick++-Q16.7.dylib   libMagick++.dylib
ln -s libMagickCore-Q16.7.dylib libMagickCore.dylib
ln -s libMagickWand-Q16.7.dylib libMagickWand.dylib
gem install rmagick

if your project uses bcrypt-ruby, you'll need to:
sudo ln -s /usr/bin/gcc /usr/bin/gcc-4.2