Well guys, It still isn't fixed.

1998 Buick Park Ave w/ ~120k and 15k on cheap Goodyear tires.

The tire shop told me it was an alignment problem. The alignment shop said it was a tire problem. The mechanic said it was an engine mount and rotor problem.

I replaced front and rear mounts (had to pay a mechanic for the rear trans mount) , replaced all rotors and brake pads, had tires inspected, balanced and rotated, and paid for an alignment. None of it amounted to a hill of beans. I have twice paid for an inspection of the vehicle to discover all possible sources of vibration and specifically asked both shops to check the hubs. I checked them myself but I'm not an expert and wanted a second opinion. Everyone said the hubs were fine and that they were definitely not responsible for my vibration problem, so today I jacked it up and let the tires run in another attempt to figure it out.

Check this out: buick3 - YouTube

The front right tire is fine. The front left tire catches, drags, squeels, and generally misbehaves. The video doesn't show quite show how badly the wheel catches and lugs the engine down but you can hear it pretty clearly. It'* awful. How can two professionals charging shop rates miss this!? Was I paying them for the best guess? Obviously something is wrong here and they missed it even though I stood there and pointed at the area I thought was causing a problem. Damn waste of money.

So.... if this is not a hub issue then what else could it be? The problem was not made better or worse when replacing rotors so I doubt I interfered with anything there.

I'm looking for a sure diagnosis before throwing any more money at this problem. Whaddya think?

There is only one sure fire way to tell if it has anything to do with the rotors/brakes. Get 2 pieces of 2x4(or whatever you can put between the pads) about the length of a brake pad. Remove the calipers, place 1 piece of 2x4 between the pads in both calipers and repeat the same test you did in the video. You can even keep the wheels removed, just use 2 lug nuts on each rotor to keep if from falling off.

Two weeks ago the brake light on my Buick started going haywire so I decided to hunker down and change all the offending components at once. There was a small but definite click in the hub with the tire installed that couldn't be felt with the tire off, and the rubber boot brake piston was torn all the way around. They're both gone now and the result is much better. The brake light turned off too.

The steering wheel isn't doing the little hula dance that'* been driving me crazy and I can actually feel the character of the tires below me. Better tires would still refine the driving experience but they were absolutely NOT the cause of my problems as I'd been told before. The axle nut came off easily but the 3 bolts holding the hub on were a pain in the ***. I couldn't access them with a 6 point socket with the cv boot in the way and the leading bolt was so corroded and packed with salt corrosion that the head nearly twisted off before it started backing out!

Sean glad u got it sorted out and things are better now.
I have learned from other GM'* that when I do brakes especially approaching 100k miles, it is time for all new. When I bought my 97PA back in Feb, it needed brakes all the way around and I got a ton of parts for it. New Raybestos rotors pads and calipers X4 got installed. Bleeding with new fluid and the car is now happy. My hubs passed inspection however, I will do all the hubs at 150k to be on the safe side on the next rotor/pad replacement and hopefully just get away with lubing the sliders on the existing calipers.
As I do alot of highway driving, I am very picky about tires and wheel balancing.
Since the car is a large sedan, and the car came with 8-10 year old tires I found the Michelin Destiny on sale. 140k warranty and fairly thick /stiff sidewalls that I will rotate every 7k and re wheel balance every year. (35k)
When it come to balancing I ensure it is done on a digital screen modern balancer.
Best of Luck on your PA they are a good smooth riding car.
Nothing worse than have your car run away with a poor balance & bumpy ride!

Yep, I'm actually discovering that I'm quite sensitive to vibration. I ride more than I drive and some motorcycles drive me crazy. Anything out of balance is a constant distraction and the high frequency vibe inherent in a lot of inline bike engines wears on me pretty quick. My kaw zrx1200 is a major offender. Cars are more utilitarian and I only desire a smooth pleasant ride that doesn't totally disconnect me from the road. Whenever it'* affordable I'll get new rubber all around for the Buick.

I should have planned to do all pads and rotors from the very start, but I did install speed bleeders all around and flush the system with a few bottles of fluid.