I always find choosing a car to buy starts out good fun, then I get looking into them in depths via forums, reliability surveys and owners reviews and things start to get tiring!
Only you can decide, if its a want or need car will make you lean towards something. I guess with you saying a diesel estate you want something which can easily take luggage and be economical at the same time.
The 307 and 407 SWs are nice cars, both good value and use the reliable engines. Id go for the later 307 with the facelifted nose and 16v engines. DOnt forget the 2.0HDi 110 in the earlier 307 has FAP equipped, only the 1.4 and 2.0 90 dont in the 307. I have driven a 307 SW, it drove very nicely and the ride was fairly good actually. I like the long dash and driving position too. Unfortunately it was a 1.6HDi running on petrol so I didnt get all that far
407s are basically a C5 without the hydraulics, again they are nice cars and the SW makes a good tourer.
I think my views on the C5s are well known on here now, obvious by how many are in my sig!
Our 05 C5 estate is a great car, comfortable, extremely refined, spacious, well equipped etc etc. Citroens hydraulics still shine through and provide a nice ride with self leveling, the estate can also be lowered and raised independently at the rear. They are great value and reliable. The 16v HDis are superb, very economical.
I looked at Mondeos a couple of years ago, around 03-54 in year with the 2.0 TDCi engine. I looked at and drove a few but I was left a little disappointed, it was a car that I had liked for some time but it didnt impress. I think I might have seen bad ones but most had rust showing on the inside of the rear doors, some in other places. The Mondeo forum revealed that the engine likes to eat through injectors quite regularly too. Saying that a friend has a 2.2 Titanium on an 05 and its very nice, even has air conditioned seats! The big wheels on the range toppers seem to ruin the ride though.
If your wanting a Ford then id go for the newer shape Focus Estate or the new Mondeo Estate, though that might be too expensive still. I do quite like the new Focus, plus they use th 1.6 and 2.0 from the PSA range, just avoid that awful 1.8TDCI!
Ive no idea about Alfas, the 159 does seem too new to be available for under £5000 though?
