Need help for implementing DAL in a 3-Tier Application

Question

Hi All,
I am working on a 3-Tier Application using ASP.NET.
While implementing DAL I have 3options in front of me;

1. Generic DAL
2. DAL with separate classes for each operation sets.
3. DAL with Retrieve, Update, Insert and Delete classes.

The database will be only on SQL server 2005 and DAL will be accessed from the Web service.
So any one help me to chose the best option among these to implement DAL.

Thanks.