I think it depends on your circumstances and how you define luxury i suppose.
If you don't need it, its a luxury? Well, i don't need a big mac but i wouldn't describe it as a luxury - however I would offer a BJ to my DP to go fetch me one (everyone knows this).
I can't afford to go camping - does that mean its a luxury (for some maybe, but i'd rather boil my head)
We have a mercedez car, albeit old - i do not consider this a luxury its good value for money is what it is - we paid 7K for it (probably too much) 9 years ago - it only has about 100,000 miles on the clock but mercs are good for 200,000 we have only ever had to have it fixed once and it cost us £70, we will probably have it for another 9 years.
I like Chai latte - they are only £2 but they FEEL like a luxury - some days £2 might be more than i can afford so i wouldn't have one.
I really don't consider a car to be a luxury in this day and age - you would spend far more money and time on public transport and its horrible (ok some people have to commute, so its a bit different) My DP could not do his job without the car (technically he needs a van but we can't afford it just now - that would be a luxury and we wouldnt have to use the mercedes as a builders van
)