If it comes down to budget though, I would buy the best suspension possible and go with V-brakes rather than disc. You can upgrade one later fairly easily while a better fork and rear shock can be horrendously expensive. Of course, having said that I know notice you are on the damp side of the Cascades. Disc brakes work better in wet conditions. Mechanical are the easiest to maintain.
FS for the same reasons as tomgrrl. I also climb much better because the back wheel maintains better traction and doesn't require as much power over obstacles. No need to lock out with a good pedal stroke.
Not so sure about "all mountain" vs XC. Depends on the terrain you'll be riding. An all mountain bike can be significantly heavier. In addition, an all mountain bike can have a long wheel base which is great for the fire roads of California but can take a lot of the fun out of the really tight narrow singletrack of central Oregon.
Do what you can to rent different types and ride the trails you want. Look at what others are riding and ask them why and if they would buy something different if they did it all over again.
When you travel from one region to another, you will see that people ride vastly different bikes with different components and tires because of regional terrain. What is optimum in Moab isn't optimum in the Cascades. Go hang out with the local clubs and see what they are riding.
When all is said and done though, make sure the frame and fork are the best you can get for your budget. The rest can be upgraded over time.
Frends know gud humors when dey is hear it. ~ Da Crockydiles of ZZE.