08 Spec Sequoia Elite, 98 Spec Hardrock Sport, 04 Spec Stumpjumper, 93 Burley Rock n Roll, 11 Trek Transport
Nice. You could win a lot worse than that.
Specifically, what brakes does that bike come with? Oh, and by the way, with an ALU bike and a straight blade ALU fork, I'd be stuffing the fattest tires I could on that bad boy (no pun intended) just to take the edge off.
Never mind. Looked it up. I don't know anything about these.
As others have noted clean the discs, you can use a degreaser or alcohol. I am almost ashamed to mention it but I use a pressure washer, I get a lot of dirt on my silver bike and use it to clean it off, blasting the rotors has always quieted them for me. Also clean the pads. If they're soaked with contaminants then they would need replacing.
Finally an adjustment might be in order. How varies a little with the brand but most require you to loosen the bolts that hold the caliper onto the mount just slightly, this is usually different than the bolts that hold the entire assembly to the frame, then rotate the wheel and mash the brake lever to center the caliper, then carefully re-tighten the bolts with the lever tightly pressed. After that reseat them by mashing them hard while riding, the harder, quicker and for longer you do it the better but be careful with the front ones so you don't go sailing over the handlebars.
The only advice I can give is make sure your wheel bearings are properly greased and adjusted. My rim brakes were squeaking badly and over the winter I bought the cone wrenches and Park grease, went ahead and cleaned, regreased and carefully adjusted the cones to make sure there was no play and no more squeaky brakes!