Volvo models I would avoid

66 & 340 with CVT - If you can find one that still works, drive it and you will understand why.
The 66 was prevoiusly the DAF.

480 1987 - a very exciting "spaceship" like car, but the first year of product had a lot of electrical problems.
This was also built at the NedCar factory in the Netherlands.

740 before 1988 - the models after are more resistant to corrosion.

740 GLT with 16v motor - the 16v head was not up to the job, several have need extensive repair

760 - The French engine is not up to Volvo standards.

 

Volvo models I would recommend

740 GL 1988-89 - good resistance to corrosion and not much electronics that can go wrong.

245 DL 1985 with B200K motor - Solex carb instead of the Stromberg carbs. 
The engine was mostly sold to Finland and other countries where sub 2 litre engines give or gave a tax-break.
The Stromberg carbs have a habit of eating litres of ATF oil (oil dampened design).

164E 1972 - the old design of body with external door handles etc but with the new injection version of the 3-litre straight six.

965 3.0 / v90 3.0 - unusual to find the 3 litre / estate combination, most 3.0s are saloon cars.
Much better engine than in the 760.
The last real Volvo.