I think this is a classic post that everyone should read:

The Most Useful .NET Utility Classes Developers Tend To Reinvent Rather Than Reuse

Related Reading: JavaScript: The Good Parts Head First Java, 2nd Edition Effective Java (2nd Edition)

If you read Creating SqlParameters Best Practices you will find the fun you have if you have null values:

SqlParameter[] sqlParams = new SqlParameter[] { new SqlParameter("@Required", required), questionCode == null ? new SqlParameter("@Code", DBNull.Value) : new SqlParameter("@Code", questionCode) };

Here is a nice helper function to deal with nulls without having to manually [...]