You have a faulty break light switch.

Take into your auto parts store like advance auto parts and see if they can scan for fault codes before throwing money at it.

If your rotors are warped that would most likely be the cause of the clicking noise. If you can feel the brake pedal pulsing when you brake it's time to fit new pads and rotors, don't forget to break them in gently. The only other thing I can think of that could make that kind of noise would be wheel bearings but my money's on the rotors.

I believe that you are experiencing false abs activation which is usually caused bt=y a bad left or right front wheel speed sensor. This is diagnosed with the use of a scan tool and a road test while viewing live sensor data of the speed sensors. One of them will read incorrect or not at all sometimes. *Usually*

After re-reading your details I agree about the master cylinder possibly being the cause, but I have never seen a bad master cylinder only fail under hard stopping, never. A bad master is a bad master and if you are sitting still and you play with the pedal some the pedal will usually sink down like you describe. But, if no other place to go, change the master and see.

You should check the condition of the fuse and relay in your ignition system. Try to check out this link http://www.automd.com/diagnose/inspection to have an idea what to check if you ignition system won't produce spark.

Visit this site and follow their instructions to test the brake booster.

http://www.ehow.com/how_7507543_test-brake-boosters.html

have your master cylinder checked unit may be bad and thers a sensor on the unit they go bad also

If piston in caliper is not moving correctly then you will have to either replace seals in piston or by a new caliper, It could just need fluid bled to get air out.

The calipers are designed to be "floating". The bolts that hold the caliper on are suppose to float freely in the bushing. This allows the caliper to "self adjust" when you put on the brake, that way even pressure is distributed to the inner pad and outer pad, since the caliper piston is only on one side (inner). There is really no way to correct a frozen caliper except replace it, they are cheap and not worth trying to unstick a frozen caliper pin. Its just not worth it. Road salt, water and dirt and corrosion all contribute to this "time honored" problem. If you ignore this issue, you will have uneven break wear, excessive pedal effort and likely you will ruin a rotor pretty quickly from overheating or simply the inner pad grinds down to nothing and the squeal sensor is never engaged because the frozen caliper won't catch the outer pad.

front sencers need to be removed and cleaned.When they get dirty the abs will actervate when comming to a normal stop ( just before you come to a compleat stop)

Start with the wheel closest to the master and end with the one the farthest away. If you've been opening the bleeders and just pumping the pedal you most likely have a whole lot of air in the line now so it may take a while to get it all out. Have you checked you proportioning valve?

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I need to know what the problem was before you replaced the booster, but, aside from that, the booster will not cause a pedal to go to the floor when it fails. The brake hydraulic system will cause that. Could be a bad master cyl or a leak in a rusted through steel brake line. I am always fixing these kinds of problems every few weeks.

Ceramic pads are usually the logest lasting, although with some rotors and vehicles cause premature rotor failure. I would suggest going with a high performance manufacturer, which you can find on aftermarket part supplier's web sites like Summit and Jegs. EBC and wilwood both make great products, however any product that meets manufacturer standards will work satisfactoroly.

per axle, both sides

The ABS light comes on when the ignition is turned on for a bulb check, then goes out after the engine starts. If the ABS warning light remains on or comes on while driving, you have to diagnose your vehicle with a scan tool capable of reading ABS troublecode.