SQL Everywhere should be included in your list. This could very well be the local storage engine of choice in the future.Now renamed to SQL 2005 Compact Edition, presumably because it sounded too much like SQL Anywhere ;-)
As you note, the Compact edition is designed to offer local file storage for the single PC. It may be called SQL server but it has no stored procedures (which may create difficulty for the "SP is always best" brigade ;-) ) and is missing a few T-SQL features as well. In many ways it seems similar to an EXCLUSIVE dbf... except that it has data in one file rather than separate dbfs, apparently has decent merge functionality with its larger siblings, AND offers Windows EFS that should make it a lot more secure than a dbf.
So you may be right. The small footprint is certainly a lot more interesting, as is the ability to use it on handheld devices as well as workstations. Smart move by MS! Do you have any idea about performance?
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1
