How important is bass to you?

I like it. A lot of people do. It can sound really good or really bad, and will not hurt your ears like that darn airy treble can when things head south.

I like to be able to feel the bass naturally when it is present and not just hear it. Midrange is lovely and music's bread and butter (where most music occurs) but bass gives music impact and "meat on the bones" that one needs to be fully sated.

20Hz-40Hz is quite a range, I meant below, say, 25HZ.
Of course 'well played' is more important, but if you can't really hear it - it makes no difference.
Not only crossover and room are critical but electronics too. Some people upgrade their speakers too quickly, many speakers are in fact better than they might seem. There is a lot that can be extracted from one great 8" driver including low bass. Not the best bass possible, not at all, but quite satisfactory.
Good bass/great midrange vs. great bass/good midrange. That's tough. I would have to listen, this can't really be decided in general. But midrange is most important, no doubt.

Nothing but mud below 25hz, explosions excluded. I like a system that at least reaches into the low 30hz range to sound realistic on a broad range of material. I prefer a punchy well timed bass with a good dose of slam over a fat thumpy bass most of the time. However, on a lot of my 60's hard bop jazz, the ported bass from the N802's add some juicy embellishment that is hard to resist.

Other deep bass suggestions: Bela Fleck, Flight of the Cosmic Hippo, and James Taylor, Hourglass

Inna-

I tend to agree w/ your situation. As a Jazz Head, I too, enjoy correctly reproduced Bass. There is a plethora of it in both LP/CD discs. We know that it is buried in both grooves and bits. In 2015, we (audiophiles) deserve the very best gear that can extract all of this wonderful information. Acoustic and electric Bass is where its at.

Keep me posted & Happy Listening!