1.8 liter petrol engine vs 2.0 liter diesel engine

Depends on your usage scenario. The petrol will be better in terms of maintenance and power. Whereas the diesel has more torque, and slightly better at fuel economies some time. More details would help a lot.
 


Generally agree except the comment about acceleration. Under normal driving conditions I would expect the petrol version of any car to have better acceleration. Usually the diesel version is heavier and will have a turbo to get the performance required and therefore suffers turbo lag

 

You are right. Turbo lag does cut off some of the initial zing that a petrol will not experience. My bad. Edited my answer.
 


In the UK many studies have shown you need to drive more than 12-15k miles a year for a diesel to be cheaper. Also it looks likely tax on diesel is set to rise. Also you need to consider what type of journey you will be making, modern diesels do not like short town driving, if that is your type of driving then expect expensive problems with the DPF (Diesel Partial Filter) and replacing a DPF starts about £800 and goes up from there depending on the car.