Don't know what the best production luxury car in the world is, but I know the worst production car, because it is a luxury one.
I met a guy who owns one, says it cost $120k new and was suppose to retail for $400k plus. The back seats massage and recline! surf
for maintenance free, low key, everyday use and runs to the grocery store in luxury http://www.lexus.com/models/LS
Picking the best luxury car is very personal. They're all nice but some cars listed here just make me cringe. I guess many like driving around with a billboard advertising net worth. On the other hand, if it's your 3rd car go for it, and you should have indoor parking for all 3+, got to have extra room for motorcycles. Some days you just want to pull upto the country/yacht club in something special.
Red neck luxury for me: Camaro, 4rd Gen, supercharger, racing tires: luxury of 1G turns when needed, luxury of accelerating like a bat out of hell, luxury of effort free driving via rear wheel drive and rack and pinion steering... I'd forego the umbrellas that pull out of the doorposts of the banker cars, I probably wouldn't even miss that feature
Not sure if it qualifies as luxury, but the Defender 110 has to be one of the coolest and most timeless designs. I think somewhere in the neighborhood of 75% of all Defenders produced in the past 50 years are still on the road, and if it is good enough for the Queen of England, and James Bond... ...although I think it looks best when you put Lara Croft next to it, or a cheetah sitting on its hood. I'm not sure if this one is street legal (the suspension seems like it might be raised too high), but I will bet no one cuts you off.