Not this again. A discussion which will be largely filled with opinion tainted with the fact the people posting it will have spent thousands based on said opinion, therefore have convinced themselves whether true or not that they bought the best car.
The good thing about diesel is the ability to return more miles per gallon of fuel than a petrol engined equivilent. This means longer tank range and less spend on fuel overall. Whether this is worth it or not depends entirely on the amount of miles you actually drive versus the potential reliability issues on the diesel v the petrol.
Rilot is correct in that 'You cant tell its a diesel' is a load of rubbish, it is, of course you can tell its a diesel in much the same way that anyone with half a brain can tell the difference between a V8 and a Straight Six, or a turbo and a non turbo, or whatever.
As for people going on about noise levels at motorway speeds - way to miss the point. Diesel engine noise at 70mph cruise has never been an issue - it wasn't an issue in my crappy old Xantia 1.9TD so it certainly isn't an issue with todays cars. When people talk about noise, it's at lower speeds - around town, you can tell, and some of us find that intrusive, end of.
I much prefer the creamy smoothness of a nice petrol engine around town. It's quiet, it isnt instrusive and you cant tell the engine is running when sitting in traffic. This is lovely.
When it became clear that the life of our E39 530d had become one not of long trips but of general day to day town use, it went and was replaced by a petrol six instead. Obviously this is because diesel is better.
But that isn't to say I'd never have a diesel - if when I come to buy my next car a 245bhp variant 330d appears with the right spec and colour combo I'm hardly likely to dismiss it just because its a diesel. What I wouldnt do is buy it then go on a crusade to convince everyone else you cant tell its a diesel. Insecurity much?