7th gen Pontiac Grand Prix (my parents have owned a few, and they're great cars)4th gen Buick Regal (avoid '97s) (I own one, and know people with them)
8th/9th gen Chevy Impalas (I know a number of people with them)
10th gen Pontiac Bonneville (my brother owned one)
You get a Series II or III 3800-powered car, look for common issues before buying, she looks solid, do the right maintenance and it has a chance of getting to 400k. I've seen many, many of the above cars reach 250/350k miles and still be running strong.
The 97-03 W-body buyers guide / Common problems Use that as a general guide on 3800-powered cars before buying, look for those issues/symptoms.
I'd avoid the Ford Taurus, I have three friends whose families have them - they're mechanically reliable mostly, but the frames/subframes are sketchy at best (especially the Taurus' sister the Mercury Sable) as far as rusting out (they rust even worse than 6th gen Grand Prixs, lol), and have literally no power. You could wait a year for that car to go anywhere. Good mileage though. And, knew a guy who was driving a Taurus down the interstate and the rear underside of the car literally rusted away and came off.
my $0.02