From our ownership:-
50k - 80k Rover 25 TDi. Fairly unrefined & not particularly edonomical, but got the impression it would just go on & on.
60k - 70k Rover 420 SLDi. L-Series engine I think. Got the impression these were bullet proof. In the time I had it is was fine.
19k - 40k Rover 25 TDi. L-Series again. As above. No problems at all.
60k - 98k 04'Toyota Verso 2.0 D4D. Nice engine. Not aware of any major issues. Had a split turbo hose, but can happen on any diesel. Towed caravan with it.
130k - ongoing (170k now) 52' Mondeo 130 TDCi. Wifes regular commuter (20 miles dual carriageway blast each way). Sounds awful but drives lovely. Loads of torque. Towed 1500kg caravan with it with no issues. Split turbo hose once. Flashing Engine light & limp mode once, feared turbo / injectors. Garage recoded the injectors for £100. Fine for last 15k. Mechanic said Mondeo TDCi issues arent as common as the internet makes out. That theres thousands of them out there, & when they do go they are fairly cheap to fix.
60k - ongoing (90k now) Ford Galaxy 130hp TDi. (VAG engine). Probably the best diesel we've had. Drives nice, sounds more refined than the Mondeo, but not as good as the Toyota. Would happily buy another.
When we've paid off all our car loans etc, I'm going to look at leasing. I like the concept that its a new car, any problems will be covered & I'm not too fussed about "owning" a car any more. If I can pay £50 a week, drive something thats safe for my family & is covered for any break downs then I'm happy.