Don't Use Clustered Indexes?

Hi,

The more I read, the more confused I'm getting ! (no wonder they say
ignorance is bliss)

I just got back from the bookstore and was flipping through some SQL Server
Administration books.

One says, that to get the best query performance, youi do two things:

1. Cover all the columns used in each SELECT (including the WHERE, ORDER
BY , etc.) with an index

2. Make sure it's a NON-CLUSTERED index.

In this way, the author says, you avoid ever going directly to the base
tables for data to resolve the query - i.e. it's resolved in the index.

So, for example, he argues if you have:

SELECT Lname,Fname, CompanyName
from Contacts
inner join Customers
on (contacts.custid = customers.custid)

that you use two non-clustered indexes:
1. Lname,Fname and custid from the Contacts table
2. CompanyName and custid from Customers

(as opposed to the standard approach of a clustered index on the PK's of
each table)

He says that clustered indexes don't speed up performance because they're
the same as a full table scan. Should I drop clustered indexes from my
large tables, given that there are multiple non-clustered indexes on them?
Is it better to just use multiple non-clustered indexes on a heap table?

Steve