Doug, I've got an '89 740 Turbo wagon, and a '95 850 sedan, and love them both. The 240 series are virtually bulletproof, easy to work on, and have excellent support systems via the internet.
The 4 speed with overdrive is considered a better trans than the straight 5 speed.
I wouldn't hesitate to buy another older Volvo, but draw the line at the later ones. Commonly referred to as "Fiords".
Jeff