Initially I was on the fence between a Volvo V50 D5, a BMW Touring 325i/320d, Honda Accord 2.2 CDTi or Avant 2.0TDI.
I did hours upon hours of research and eventually crossed the Volvo off the list because of the relatively high price and scarcity of spares, the BMW because of the lack of spare wheel, the Honda because of the scarcity of good, clean models and that left me with the Avant as the only viable option.
I have since broadened my search to the petrol models too, as I really don't do enough miles to justify a diesel model over a petrol model.
BTW, you should check out M539 Restorations on YouTube. He specialises in restoring older BMW's and is generally quite an entertaining watch, even if he only works on petrol models.