Swedes love to take care of their belongings. Because things are rather expensive here (and wages low), the average Swede can not buy a new car every other year.
On the other hand we buy quality cars and often the more powerful engines. Hence, few diesels. But the lack of diesel cars is also due to a heavy taxation (which is currently undergoing changes). Annual tax on a SAAB 9-3 / 9-5 petrol is about €200 per year. Diesel versions about 100-200% more. Unleaded petrol is about €1.25/l and diesel €1.15/l. You do the math...
Which SAAB model is the most sought after? I would say the SAAB Sonett (version I and II).
My personal all time favorite would definitely be a SAAB 900 Turbo16S Aero 3 door, years 1992-3.