I'd seriously consider a Peugeot 406.
I've had 3 and if someones after a reliable barge I'd recommend one to anyone! I'm a moderator over at 406oc and there's numerous people over there with 300k+ models still running perfectly and still returning good economy.

If you want a purely mechanical car then the 1.9TD has a Bosch pump and can be run on vegetable oil.
The 2.1TD has 3 valves per cylinder and has much more torque. It has a semi mechanical pump that takes information from an ECU like a Focus or Transit TDDi. These can have a Bosch pump fitted from a 1.9TD fairly easy and benefit from being able to run vegetable oil.

The HDi's rarely give any issues. In fact I've never even heard of a DMF failure! Usually the clutches start slipping long before the DMF gives up.
If you go for a HDi90 then you won't have a DMF to worry about. My HDi90 with an intercooler and a stage one map was running 130bhp and returning 65mpg on a run!
HDi's rarely give any injector or pump issues either!