For the past month or so I've been noticing that when I apply the brakes, most times I'll get a super loud squeal/screeching from the front. It's quiet going down the road and it doesn't always do it (sometimes it doesn't make sound at all). But when it does, you can hear it a block away. My brakes are in good condition so wear is not likely to be the problem.

I'm going to look at the rotors for unusual wear in case a rock or something is jammed in there, but aside from that, what usually causes noise like that? Cheap brake pads or rotors?

 

sometimes its cheap parts, other times its just a funny vibration that makes a nasty noise. it can often be eliminated by applying a thin layer of grease to the points where the pads contact the caliper and any other non-rotating parts, and if necessary also on the caliper mounting areas.

 

If you are using metallic pads they can/will squeal because of the metal used in them. The more metal in them the more prone they are to squealing. Note that the "premium" brake pad line has more metal in it than the "cheap" line/brand. So if you're going with metallic pads and are concerned about noise, use the mid-grade or economy brand. Or better yet, get ceramic pads (if they're available for your make-model).

Background (copied from Brake-facts website):
There are basically two choices of brake pads: organic/ceramic or metallic (including semi-metallic pads that are a hybrid between organic and metallic pads).

Organic brakes used chopped kevlar or fiberglass as a binding agent, and metallic pads included iron powder and metal fibers. The disadvantages of metal fibers in the pad: 1) it expands and contracts to destabilize the binding agents, 2) it promotes clumps of high density areas in the pad that can cause noise and grooves in the rotor, 3) it facilitates conduction heat transfer to the piston that can cause brake fluid to boil. The advantage of metallic pads is that it had much better fade resistance than organic pads at high temperature.

Ceramic pads are still an organic pad (free from asbestos) but with much better brake performance. Ceramic has the advantage of high thermal dimensional stability and improved pedal pressure sensitivity, i.e. the driver does not have to press harder on the pedal to stop at the same rate as the brake temperature increases. Ceramic pads tend to be quiet with great all-around performance.

Most OE vehicles now come from the factory with ceramic pads. In general, I recommend ceramic pads for most street driving, and metallic pads for racing, police pursuit or commercial truck applications. There are many different brands of ceramic brakes, and some manufactures sell ceramic brakes that have metal in them. A true ceramic brake pad has no ferrous metal in it.

 

They used to sell little packs of this stuff that you put on the back side of the brake pads before you install them to help eliminate brake squeal.

 

Auto Zone has little packets of brake lube claiming to stop brake noise