Screeching while driving

I have a 96 XJ that has started making a terrible screeching noise coming from the front (maybe the drivers side) while driving. It is only while the vehicle is in motion, and sounds like a dry bearing noise. I found a failed axleshaft u-joint on the driver's side and replaced that, thinking that that was the cause, but the Jeep still makes the noise. While I had the axleshaft and hub out, I checked the wheel bearing and it was smooth and not sloppy. It is noticeably worse tonight and it is raining. I can't think of anything else that could be making this noise... The front driveshaft u-joints are all solid, no slop there, and I did not feel any slop in the front differential yoke either, so I don't think that that's our problem. Any ideas would be appreciated.

I should also add that the noise occurs when driving straight or turning, but is usually guaranteed to squeel when turning.

Thanks,
Matt

Does it change when braking?

It usually makes the noise when the brakes are not applied. However it has made the noise a couple of times when the brakes were applied.

Backing plate dragging on the rotor? Or rock or debris stuck in the brake pads?

I replaced the pads and rotors when I changed that u-joint and made sure that the backing plate did not drag. It can't be anything in the pads because it made the noise both before and after I replaced them.

Check your fan belt...mine screeches really bad....especially in rainy weather...or if I start it up and throw the lights on right away....screeches and discharges.

I second the belt. I started having a lot of squeeling all of a sudden - especially when I put the engine under load. Turns out the bearings on my alternator went bad, which loosened my belt and caused some nasty squeeling. New alternator and new belt solved the problem.

It sounds like the hub assembly, even though you checked them. You said they were smooth and not sloppy. Was this just a visual inspection? Or did you grab the tire and try to move it around?