What is a "Luxury" car?

Here's an interesting topic that's open for feedback and debate. One of the forums I frequent, GMInsidenews.com is often abuzz with discussion on what Cadillac should do to be competitive and relevant. Also keeping in mind that there is still Buick which also claims to be "luxury". The question is, what is a luxury car?
At one end of the spectrum we have BMW which bases it's marketing on "fun to drive", and pretty much invented the popular concept of the "sports sedan" (Jaguar and probably others were doing it first, but it was BMW that really took the idea and ran with it). This section values communicative steering and a taut chassis. Typically this is paired with a performance oriented engine and RWD.

The other end of the spectrum, or so I'm told, is Lexus. I have never driven a Lexus but from what I hear the idea is to have the driver in total isolation from the world around. Apparently in this category and engine isn't expected to have any "getup" and FWD is perfectly acceptable.

Then of course you can get into "ultra-luxury" such as Rolls-Royce, Bentley, and Maybach. But I'm mostly concerned with the most general definition of a luxury car.

For me these are some things that I would expect in a "luxury" car. Unfortunately nobody really makes this short of Rolls-Royce.

1) Part of the definition of luxury is "excess": A Luxury car should have the finest materials, or at least materials that are far above "average". Expect high-grade "aniline" leathers, and real wood trim. Also, emphasis on "real" materials. For instance a door handle that looks chrome should be chrome plated metal, not plastic.

2)The interior should be nearly silent. Some pleasant exhaust noise etc is OK, but road noise and wind noise is totally unacceptable. At cruising speed (60-80mph) all passengers should be able to carry on a conversation at normal household levels.

3)Ride should be tuned for comfort. frost heaves, expansion joints, and rough pavement should not be noticed by the cars occupants. Anything short of a speed-bump or pothole should be completely smothered, and even those events should be barely noticed. With today's availability of active suspension systems a vehicle with this type of tuning should still be able to have acceptable handling. I don't expect a 5,000lb luxury car to handle like a Porsche, but I shouldn't have to slow down to take a turn on the interstate.

4) While I don't care to take a luxury car drag-racing, the engine should have adequate torque to accelerate the car effortlessly within the normal operating range. If I need to accelerate from 60 to 80mph to pass someone on the interstate it should happen without drama. This means no downshifts for "passing" acceleration. Back in "the day" Cadillac typically had the largest engines GM offered. These days, the most powerful Cadillac has a de-tuned Corvette engine. (In 1957 Cadillac had a 390c.i. engine while the Corvette had a 289)

While this is possible with a FWD platform (Cadillac installed a 500ci engine with FWD), as an engineer, I believe that RWD is preferred in almost any case, and especially with a high-torque engine.

What do you think?