I'd buy the Lexus and keep it for a long, long time, enjoying the "low" price (comparatively) and impeccable build quality.
I'd lease the Mercedes and enjoy it's amazing, well, everything. MB's V-8s have risen to the top of the heap, and this new S-Class is a testament to their ability to combine engine, chassis, and opulence. That said, they're still overly complex cars that I'd have a difficult time trusting past the warranty period.
None of the others on the list interest me all that much. The RR is not a luxury sedan, the Porsche is not attractive to me, etc.