I have a 2000 Chevy Impala LS with 130,000 miles. Drives great, and even after all those miles, the car drives like new.
Everything has been great on the car, with a few minor repairs to non-essential electronic gadgets such as the rear view mirror connectors needed re-soldering because the plastic connector placed stress on the solder points, causing stress cracks, and the outside temperature sensor for the optional overhead display needed to be replaced ($10).
One minor repair that was needed that was addressed in latter models was a faulty Electronic Pressure Control Solenoid for the transmission, causing clunking during shifts (annoying hard or jerky shifting resulting from the on-board computer compensating for the failing part). A better aftermarket part is an inexpensive part ($50-$80 IIRC), but accessing the transmission cover plate can take some gymnastics for the DIY'ers. Various online forums have info on the fix and how to drop the engine and transmission for access. A shop can also fix it, but sometimes they'll want to talk you into a new transmission, which may or may not be a good thing, depending on the condition of your old transmission.
All in all, the car has been a great reliable vehicle, that has never left me stranded or had me worried.
Last year my brother switched from a long line of Impalas to the Chevy Equinox. All his Impalas (going back to the late 80's) were very good cars. He never had a problem of any kind with any of them, and the gas mileage on the newer ones was phenomenal (well over 30 mpg highway). Our current GM vehicle is flawless after almost 9 years and 100,000 miles of admittedly pampered driving.
I have a 2001 Camaro, which I keep in very good condition. I was happy to get the complimentary maintenance card that gave me four visits, which includes, "lube-oil-filter, four-tire rotation and 27-point vehicle inspection." However, the VIN on the card did not match my Camaro. It is the only Chevy I have had in quite a long time. Don't know what your records show, but they are incorrect. Any chance of getting a card for my Camaro?
Has the fuel filter been changed recently? Could be a failing fuel pump or dirty fuel injectors. Do you use fuel system cleaner at all? Do you have an excessive gas smell coming from the exhaust, it could be a plugged cat.
As for the windshield, it sounds like a leak in the windshield sealant. Have an autoglass repair company remove and replace the sealant on the windshield. Are you sure it's coming from the windshield though? It might be the cabin air filter seal. It is under the passenger side wiper. Remove the panel, replace the filter, and inspect the gaskets.
As for the airbag light, it is likely a loose or corroded connection in the steering wheel. But, in most cases it's the ignition switch.
For the stalling issue, it is likely the MAF sensor. Remove it and clean with MAF sensor cleaner, let it dry, and reinstall. Do NOT touch the wires inside the sensor!!
These are all common problems, and can be fixed rather cheaply with the right amount of experience and knowledge.
You got ripped off for that fuel level sensor big time. Most shops say it requires dropping the fuel tank, when in fact it doesn't at all. Simply 5 bolts under the trunk carpet to remove the fuel pump access panel. Remove the fuel pump connector and (3) clip on lines going to the pump. Remove the fuel pump and take a few screws out, replace the fuel level sensor, and reverse. It took me maybe 1 hour and $20 for a fuel level sensor. You got screwed big time!!