Might I add emissions and economy aside. There's more to a diesel than those..
I mainly got diesel this time round cos I have been doing a lot of towing (long distance too) and diesel does that best, pulling 2000 + kilo loaded car trailer up hills & over taking people in the slow lane is awesome. haha
The economy is just a big bonus and makes it a little more gentle on the wallet!
Now I live 8 minutes drive from my office its no problem for me to buy a gas guzzler (read X5m) and ride a push bike to work (once it warms up)!