A Diesel produces more torque, less hp, gives about 30-40% more km per liter and has about 35% more maintenance costs (primarily engine oil- change more frequently).
Petrol & diesel are currently same @ 57 rs per liter. But in future, diesel will become costlier than petrol, by as much as 10-15 rs per liter assuming petrol 60, diesel 72 or so (my estimate).
In the end, however, I prefer petrol vehicles over diesel. They are much more fun to drive (way more hp) and petrol can be purchased anywhere without lines (vans, trucks, 2.0Ds :p).
although if the gasoline alternative has to be run on HOBC, Id consider diesel as HOBC is not widely available and costs significantly more.
Insha Allah however, fuel costs will be slashed further, with oil @ $55 per barrel this month and $40 per barrel for the next and the outlook even worse. Im guessing 35 rs per liter for petrol (Y) in December.