Front Struts. Replaced after much debate at the dealer by warranty.
So far it has been a solid performer with no issues. At 85,000 miles it is ready for some basic maintenance like plugs and possibly a transmission filter. The brakes seem a bit on the weak side, but have been the same since the day I bought it 20,000 miles ago.
It is a 4X4. I prefer the 4WD system on the Isuzu Trooper much better. That truck had a more solid feel in bad conditions, but it could be down to the Firestone tires that were on the Trailblazer when I bought it.
I am surprised by the amount of compliments I get on the vehicle.
Gas mileage is about 17mpg the it gets well over 300 miles per tank on long trips.
The heater is great. The AC isn't.
Not the most comfortable for drivers over 6 feet on long trips.
Updating my last comments. The truck has over 88,000 miles now. It's still running strong. I had the transmission filter changed and do oil changes every 3,000 miles. I finally replaced the Firestone tires with Bridgestones and it made a world of difference in the handling and braking.
It still feels a little sketchy in the snow compared to some other vehicles I've had. It seems to hold it's value okay, but I think I'll hold on to it a while longer.