Good to know since it appears I now need a new radiator as well. I found the leak last night low on the far driver'* side of the radiator. It holds water when cool, but after driving it for a while it was pouring water out pretty steadily. So that answers that question, now I just have to figure out what to do with it. I won't have time to work on it this weekend so in the meantime, does anyone have a preferred brand of radiator stop leak that I could try to hold me over? I usually prefer not to use those products if I can help it, but in this case I don't have a choice.

When I've had to use such a product, the aluminum powder stuff has always worked best for me.

If the aluminum core is leaking, I'd try Barr'* stop leak. I haven't personally had success with the powdered aluminum varieties, but maybe that'd work for you - it depends on the size and location of the hole.
If your radiator has the plastic end tanks and that'* where it'* leaking, it'* time to buy a new radiator

No question about that.

Not a fun thing to find out, but an opportunity to upgrade at least.

That is a question I haven't answered yet. The water APPEARS to be coming out of the end of one of the aluminum coils, but it is right where it attaches into the plastic end, so I'm not 100% sure that it is the aluminum portion that'* leaking. I think it is, but I probably won't know for sure until I can pull it out and get a close look at it.

Don't use stop leak! A lot of that stuff on the market clogs up your cooling system, especially your heater core! (aren't those fun to fix ) Anything stopleak is bad for your car whether its P/*, transmission, and A/C. I won't do A/C service to a car with stop leak in the refrigerant because it clogs the filter for the A/C machine and it won't work(older) new ones won't even let you service the car. The only coolant stop leak I have had be ok is the GM brown tabs that you smash with a hammer. If your gonna replace the radiator just keep topping it off, its your best bet.

Stop leak doesn't always cause a blockage or problem.

Most of the time it'* fine and does the intended purpose. In extra doses by the uninformed is where most of the problems happen. It'* like adding dye to an AC system. That doesn't clog or cause an issue...it helps you fix the issue.