We at JDI are moving to a project based working method. We decided to use the tools from Atlassian, since those tools seem to do what we require. We also run a number of internal tools, and all those together mean remembering about 6 different usernames and password.
We decided to give Crowd a try : SSO, with an option to integrate with custom applications. It uses SOAP internally, and SSO is managed with a domain cookie. About a day work, but now all Atlassian tools we use, our administration system and subversion are authenticating against crowd 
