Exactly what the title says ........... any thoughts on other good relational database implementations besides SQL Server DB.
The .NET Framework needs to be able to communicate with it as well.
Oracle, Postgres, MySql ... the list goes on ...
.NET has its own libraries to communicate with SqlServer, but you can connect to any ODBC / OLEDB enabled database under windows.
Depending on what you need to do this, you can use Oracle, Firebird SQL, SQLite, MySQL, BerkeleyDB, or several others.
Lots of them: Firebird , PostgreSQL , SQLite , MySQL to name a few.
Don't know about LINQ support there.