Audiophile Bass?

delka and baclagg a proper subwoofer system requires a cross over with both low pass and high pass filters. They can then be tailored to match perfectly at the 6 dB down point that sounds best. 1/2 the advantage of subwoofers is taking the bass away from the satellite speakers. Just because a speaker rolls off at 40 Hz does not mean that it is not trying to go down to DC. It is. How many threads have you seen about pumping woofers? When a woofer bounces around like this it is Doppler distorting every other note carried by the woofer. Sometimes you can even hear the woofer flutter. For vinyl users this is a major problem. Getting concert level bass off a turntable is no easy feat. 
Papa, again, accurate bass is accurate for any bass. The best systems will do an acoustic bass just as well as an earth quake. I do not hype anything for movies. I just change inputs. I don't change anything for acoustic jazz.
I will also add that I had a hard time getting things near perfect until digital bass management came along. Most audiophiles particularly the vinylistas  have never heard this work. I could never get concert level bass off a turntable until I got a digital subsonic filter that does 80 dB/Oct from 18 Hz. Instead of spending hours critically listening and tuning I just plug in a microphone spend 5 minutes taking a measurement, plug in crossover frequencies and slope, done.

fj, a properly set up system sounds great whatever it is playing. Like mc I have a large Stewart screen between my ESLs and my system doubles for theater use and does the job nicely even though I have no rear or center channels. And given the power of my system which totals 9000 watts It actually does the job better than any dedicated theater system I have ever heard. Actually most theater systems are cheap poorly performing stuff with boosted bass so you can at least feel the car wrecks and earth quakes. 

Exactly wolf, the best subs are invisible until a low C organ note comes along. Not loud but your vision blurs. 

mahgister, I do not know if you have ever been to a small jazz club but the rhythm section of a trio or quartet is a very palpable experience. When the bass section of a classical orchestra gets going along with the tympani you also get the same palpable experience. It is accurately achieving that sensation that is the issue. I have never heard or felt a self contained speaker system do it well. Yes, it is not easy to get a separate subwoofer system to do it accurately but it is the solution if managed correctly. I hate to say this but most subwoofers on the market are hopelessly crippled by poor cabinetry, weak electronics and cheap drivers. The only subs on the market that I have been able to consistently integrate and get the right sound and impact are the JL Audio Fathom and Gotham units. My experience with other subs is limited. I like the design of the Magico subs but have not heard them yet. I prefer passive subwoofers mostly because I have outboard digital bass management capabilities and it simplifies the situation with the subs themselves not having electronics in them. I make my own subs which allows me to do stuff with the enclosures that is difficult to do on a commercial basis because it would be too expensive. Most of the distortion comes from the enclosure not the driver.  
Tom, there are some subwoofer systems that people really like like Audiokinesis's Swarm system that are very reasonable priced. All I can say is that I would never live without subwoofers and once you have experience the best bass performance there is no going back. Hang the expense. 

baclagg, Cornwalls are great speakers but they do not go that low either.
It is really the acoustics of residential sized rooms that is the issue. Speakers may be rated to get down in the 20s but as you say they have no "balls" down there. It really requires a purpose designed subwoofer system, room control and a lot of power. Having lived with subwoofer since the late 70s I can't live without them. Loud is no good if you can't feel the music. I love the visceral aspect of music. In order to get me to sleep as an infant my mother put a table radio in the crib with me. Screwed up by a table radio. 

I'm not sure what this means. The idea is to reproduce accurately the bass that is on the recording be it studio or live. The bass that people hear in large enclosed venues is distorted by echos and standing waves beyond comprehension. The last thing I would want to do is reproduce that. There is accurate and there is everything else. Reproducing the bass of a good live venue is very difficult in a small room, not impossible but close to it. I would venture that not even 1 in 1000 systems even come close. All the theater systems I have heard just make a lot of inaccurate bass and most of the Hi Fi system do not have enough energy or go low enough but do fine above 50 Hz or so.