I used Rob Conery's SubSonic project for a long time. Now I'm looking for a .NET ORM written in C#... Here's what I've come across so far.
Some newer, perhaps less known ones
- Small is Beautiful - .NET Micro ORMs
- Nice writeup on PetaPoco by Arroyocode
- Sample app showing Massive, Dapper.Net, Simple.Data and PetaPoco in action
The last link should be interesting for looking how calls are made from the first four mentioned. From all the benchmarks I've seen it seems like they are all fairly close, and beat most of the mainstream heavy ORMs like Entity Framework (EF).