gistfile1.txt

ruby - use the one on leopard
gems - sudo gem update --system
rails - sudo gem install rails
mongrel - sudo gem install mongrel
subversion - use the one on leopard
git - http://git-osx-installer.googlecode.com/files/git-1.5.6.4-intel-leopard.dmg (http://code.google.com/p/git-osx-installer/)
mysql - http://dev.mysql.com/get/Downloads/MySQL-5.0/mysql-5.0.51b-osx10.5-x86.dmg/from/http://mysql.osuosl.org/
postgres - on your own but i'm sure theres an installer, avoid macports at all costs, use google!