Your choice depends on what your requirements are. The top 3 ORMs for large projects (in my experience) are:
- Entity Framework - http://msdn.microsoft.com/en-us/library/aa697427%28v=vs.80%29.aspx
- NHibernate - http://http://nhforge.org
- CSLA - http://www.lhotka.net/cslanet/
These three above are very large and have a lot of bells and whistles. Picking one of these will depend on the level of experience of the developers. These are much slower that hand-coding with datareaders, and the lighter ORMs out there.
Here is a list of some very light and fast ORMs. I only recommend these, if the developers are very good with SQL.
- Dapper - http://code.google.com/p/dapper-dot-net/
- ORMLite - https://github.com/ServiceStack/ServiceStack.OrmLite
- PetaPoco - http://www.toptensoftware.com/petapoco/
- Massive - https://github.com/robconery/massive
- Simple.Data - https://github.com/markrendle/Simple.Data
These are extremely fast, but lack a lot of the bells and whistles associated with the heavier ORMs.
