Front brakes have been done twice in the 36,000 miles I've owned it.
Major repairs (all around 130,000 miles) were:
One expensive fuel injector (thanks to a Pontiac dealer diagnosis mistake).
Minor problems not yet fixed:
Passenger side power window switch needs replaced - you can roll it up, but not down. Passenger side window must be lowered by the driver. Not enough of an annoyance to me to replace it yet, as I'm normally in the car alone anyway.
Passenger side rear-view mirror glass fell out on the way home from work about 145,000 miles. Not exactly a big deal - just haven't gotten around to replacing it yet.
I bought this high-mileage car way too cheaply ($3,000 under average retail) and knew I was going to need to throw some money into it relatively soon after purchase. It appeared to be a solid, well-maintained car with all original parts, and that initial impression proved to be accurate.
Actually my biggest headache with this car has been the local Pontiac dealer, who misdiagnosed the real problem TWICE and cost me about $1000 in repairs that I just flat didn't really need. The real problem all along was the ignition module and catalytic converter.
After the 130,000 mile repairs listed above (which were performed by a local mechanic instead of the Pontiac dealership), the car has been dead nuts reliable with no problems at all for the last 28,000 miles.
This car *IS* showing it's age at 158,000 miles. It has many worn body bushings in the front, making for a real noisefest going over railroad tracks/sizable bumps, and it rides approximately like a go-kart. But, the struts are okay, and the exhaust system remains solid, as does the front end itself.
It remains fun to drive, looks a lot younger than it is, and everything still works at 158K miles. Doesn't use a drop of oil, runs cool, and the engine's as dry as a bone on the outside - no leaks anywhere. I drive it an average of 100 miles each and every day.
Don't let that Quad Four of yours overheat, though... if you crack the head (as some older models were known to do when overheated), that sucker's gonna cost ya upwards of $1500 to replace.
That said, I'd do this one again.