XC (mountain bike) tire for dry hardpack and loose conditions I am just looking for a a new set of tires for my front suspension mountain bike (has a newer nicer fork on it now).  

I mostly ride in the Gatineau Park in Eastern Ontario.  The conditions are almost always dry.  There is quite a bit of loose gravel and a good amount of hardpack.  The terrine is pretty hilly and occasionally I find myself loosing traction on my rear tire while climbing.  

Right now I am riding a pair of stock tires.  Both tires are pretty cheap.  


Rear tire.  
Front tire.


Am interesting in upgrading to get a bit more performance out of my bike.  Would also like to reduce the rolling resistance.  

Couple questions: 


What difference will more expensive tires make?
What width of tires will work best for the conditions described?
What price range is reasonable for a good set of XC tires?
Any other pieces of wisdom I should consider when choosing tires?
Any examples of good tires for these conditions.
A good quality bike tire usually has a better size tolerance, a better rubber compound (might make more difference on traction than thread geometry itself), a better seating on the rim, and a better "feel" - the tyre carcass reacts better to bumps and curves, have a good cushioning effect and a good rolling resistance. I'd say there is a perceiveably relationship between price and quality, or at least the vast majority of low-price tires are not very good compared to medium- to high-priced ones;
For the described conditions, I'd say 2.0 would be best, some might prefer 1.95, some up to 2.2. More than this is possible, but probably not necessary;
Cannot tell about price range, depends on country;
Tires are funny in a way that the best tires (so as the best suspensions) do their work quietly. If you notice that you just GO, enjoying the trail and never ever having to think about the tire, traction, cornering control, pinch flats, etc., then the tire is good, it's doing its magic. Not-so-good tyres constantly remind you they're there, and you end up thinking: "this f***ing tire sucks!";
Tire models/brands are a very personal matter, but I had good tires - ones that did their magic - from (not in any order) Bontrager, Specialized, Maxxis, Ritchey, WTB, Panaracer, Tioga.