I am working on a C# 4.0, WPF 4.0, SQL 2008 project and I do work at home and in the office. I just setup SubVersion using Visual SVN per the recommendations found in other ques
Can't you change the .config at home and not check the change to the connection string back in?
Holding connection string information in code is bad practice (anyone can use ildasm.exe and see all the strings in your code).
This kind of information should be in configuration which you have better control over.
Additionally, .NET supports encryption of the connection string section, if needed.