What is the difference between a Will and a Revocable Living Trust
(RLT)?  Are all Wills and all RVT's Probated?  What is the actual or
average cost of Probate?  If one's estate is less than $1.5 million,
which is preferable, a Will or a RVT? What are the possible estate tax
implications for such an estate?

Have you read through FindLaw.com? That site has many, many facts on
Wills and Trusts.

In most instances a Revocable Living Trust is preferrable to a Simple
Will since assets titled to the Trust will avoid probate. Probate
lengthens the estate settlement process and is subject to public
record.
A Revocable Living Trust could also provide for management of assets
for the benefit of your heirs and protection from creditors and
predators.
A Revocable living trust goes hand in hand with a Pour-Over Will which
controls the distribution of assets not titled to the trust.