Excellent advice guys, and thanks! I've been out of town for a couple of weeks, so I haven't done anything with this yet, except for the "tear it down and leave it apart in the driveway" phase.
The neighbors love it when I do that.
I did the entire front brake system last year (calipers, hoses, hard lines, pads, resurfaced rotors), but the rotors are looking a little beat. Rather than packing new bearings in the old rotors again, I think I'm going to get two new rotor/hub assy's, new bearings, races, and seals, and put the whole thing back together. Probably add some quality pads like Hawk's or Performance Friction's. I smoked out the current el cheapo front pads last year when towing, so it's probably a good idea anyway.
I'll update on the outcome, and whether or not the howling continues, just in case it'll help someone else.
Thanks again guys!