Sounds like a wheel bearing. Do you have a mechanic's stethoscope, or a large screw driver. I would jack up and with the wheel off, put the screwdriver or stethoscope up to the hub, have an assistant turn the wheel, and listen to hear if the noise is coming from the bearing. With a screwdriver you put your ear onto the handle. Mechanic's stethoscopes are better, as you do not have to have your head under a jacked up car. You can always compare sides to help confirm your diagnosis. Best to do this turning the axle by hand, not using the motor to drive it, the motor will add lots of extraneous noise to hinder the diagnosis.
To check uni-joints I would lift up and down on the joint and see if there is play there. Sometimes you will hear a metal on metal click. Bad uni-joints come and go a bit with the noise they make, while driving in my experience, and make noise under braking, and under acceleration.
Sounds more like a wheel bearing to me. If you replace the wheel bearing, make sure you change the collapsible spacer as well. I think they are a little tricky to do, I would seek advice from someone who has done them first on here.
James.