LLBLGen . The current version 2.6 is awesome. The developer is really easy to use, supports object inheritance, type converters (which can also be used to bridge the gap between the various types in the RDBMS), validation, auditing, authorization, and even tons. Most importantly, their documentation is stellar and their support forum is very responsive. The lead developer (also located on stackoverflow) also answers user questions. I canβt say enough about this tool, try it. It's worth it.
The next version is likely to hit the rest of the game. In addition to being able to generate your traditional data later, you will be able to generate nHibernate files, an entity framework, and linq2sql.
LLBLGen Entity Framework nHibernate (, , ).
http://www.llblgen.com/tinyforum/Messages.aspx?ThreadID=12811
http://www.llblgen.com/tinyforum/Messages.aspx?ThreadID=14659