Squeak. Bearings, brake pads????

Need some educated guesses. I have a very annoying squeak coming from the front of my '00 XJ. At first it sounds like a belt (everyone that hears it says that first). Then you realize it doesn't change with RPM's and I can't get it to happen just reving the engine while parked. It starts at about 25mph and will go away eventually or doesn't happen at all. 2WD and 4WD don't change it. Stepping on the breaks doesn't change it. Wheel Bearing? I think the cold is making it worse. THANKS!

Could be a bad wheel bearing, or maybe a dried up u-joint squeaking.

Didn't think about the U joint. Can that be greased or do I have to replace?