Great, thanks nateo and ItsPossible. With those comments in mind, I’d like to go over my understanding of my water profile. Everything below arises from things I’ve learned on John Palmer’s site
http://www.howtobrew.com/intro.html
. If either of you or anyone else would be so kind as to read this over and point out any errors and answer a couple questions, I would be ever so grateful 
Here’s my water profile:
Alkalinity - 33
Calcium - 15.7
Magnesium - 4.9
Sodium - 15.3
Sulfate - 6.8
Chloride - 35.4
Bicarbonate:
If Alkalinity is HCO3 - 33
If Alkalinity is CaCO3 - 40.25
Softness:
I’m concerned about the Calcium and Magnesium levels. My understanding is that if these aren’t high enough, there might be problems with enzymatic activity during mashing, which I take to mean the mash will be low in fermentable sugars. Is this true? If so, is it easy and cheap to make alterations to these aspects of my water profile? Also, am I correct that pH is the primary factor determining how dark I can go with the water from my tap, and that nutrient levels just determine “maltiness”?
Alkalinity:
If I plug the Caribou Slobber all grain ingredients into the EZ Water Calculator
it returns a predicted pH of 5.65 whether I select Alkalinity or Bicarbonate in the last column. This is just outside the ‘ideal’ pH range (5.4 - 5.6), but close enough that I think it would be worth making that my cut off for darkness from a pH standpoint when I start exploring all grain brewing.
Other Factors:
Regarding the less “critical” factors (Sulfate, Chloride, Sodium), the EZ Water Calculator implies that I can expect enhanced maltiness (Chloride/Sulfate ratio of 5.1) and subdued hoppiness (low sulfates). This is fine for me, as I like malty beer these days, and figure I’ll know enough to compensate should my tastes change someday.
Overall:
It seems like the alkalinity will allow me to brew with some darker malts (enabling brown ales), but the softness will downplay the malty flavors, while the low sulfates will help prevent the hops from becoming overpowering unless that’s my goal. Does this sound about right? Finally, if I wanted to brew a stout or black beer, would I be better off sticking to extracts or treating my water?