Let's just settle that the issue is not Dermal Armor.

There are a number of other cybermods, SURGE edges and adept powers that do the exact same thing as Dermal Armor and/or state in their descriptions that you are effectively using some type of armor (cyberlimbs, bone-lacing, SURGE dermal deposits, plating, dermal sheaths, mystic armor, Improved Attribute: Body, etc).

That being said, the choices are reduced to their simplest terms, and it all depends on where you draw the line (ie. how you interpret the rules):

a) Either Combat Spells ignores absolutely all armor.
b) Or Combat Spells ignore normal armor but not armor which has Body-enchancing effects (of which there are several).
c) Or Combat Spells ignore normal armor but not all internal (meaning implanted or natural) armor that is integral or innate to the target.

An even simpler point needs to be covered, though. What is "armor"?

While dermal armor sounds like armor, is it really armor? Does something have to provide an armor bonus (as in ballistic and/or impact ratings) to be considered armor? Is dermal armor armor or is it a structural enhancement? What about cyberlimbs?

I would allow body boosting effects (the long list Synner points out) to protect against body targeting spells but nothing that provided an armor bonus (as in ballistic or impact ratings).

Shadowrun 3rd Edition, page 283, "Armor:" "Two types of armor exist in Shadowrun: dermal armor (cybernetic or natural) and external armor." It goes on to explain that dermal armor works against any attack by increasing Body, period. It then goes on to explain that external armor comes in Ballistic and Impact ratings. The parenthesis comment means that dermal armor can be natural or cybernetic; not that it's necessarily either.

Critters, page 18, "Body:" "The first number is the rating. The second represents armor, if any, which functions as both ballistic and impact armor."

A critter's armor is clearly and without question described as having ballistic and impact ratings, only. There is no mention that it improves Body, nor that it is magical in nature, nor that it's dermal armor. Whether this is a mistake or not is debatable, but by the rules, that qualifies it as "external armor" for purposes of the rules. It may be natural by description, but that doesn't mean it's not considered external for purposes of game mechanics.

Shadowrun 3rd Edition, page 178, "Category:" "Combat spells ignore the effects of armor and non-magical, external protections."

Good quote DF. I reverse my earlier statement. Dermal armor doesn't help you against combat spells any more than regular armor or critter armor.

You'd still get the boost for cyber limbs, etc, unless someone has a quote for that, too

Great quote Doc, and one that settles the dermal armor et al issue as well. Of all the page references in the index we hadn't thought to look in the Gear section when it came up.

Thanks as well for allowing for the possibility that there might be an inconsistency in the way a critter's natural and innate armor is addressed in the current rules.

I'm interested in seeing what my group will make of this, since even the person who opposed critters' natural armor functioning against spells believed a troll or augumented person's Body-enhancement worked.

There is only one problem with Doctor Funkenstein's quote from critters. If we take that quote to mean exactly what it says, and further take it to superceede conflicting rules in SR3 (which is the standard for any newer SR releases, if I'm not mistaken) and then take a look at the bottom of page 19, at the description for Troll (Body 8/1), we come to this conclusion:

the second rating represents armor, if any, which functions as both ballistic and impact armor, and hence the troll has 1 point of both ballistic and impact armor, but no extra dice to roll...

It's inconsistencies like that which makes SR rules interpretation so much fun!!!

Which again, suggests to me that they were trying to "correct" the problem.

That line in the Critter's Book (page 19, bottom line) is obviously wrong. It should read "8(9)", not "8/1".