How loud is loud, What DB is actually loud?

85db at 1 watt at 1 meter 1 meter is far inside a car...
88db at 2 watts
91db at 4 watts
94db at 8 watts
97db at 16 watts
100db at 32 watts
103db at 64 watts
106db at 128 watts
109db at 256 watts and so on.
Imagine what it takes to get to 170db if you keep doubling your power to gain a measly 3db? You need to gain about 10db to double the perceived volume. Even with 102db speakers (which are rare), it takes more wattage than any amp I've seen to get 170db. I imagine that it sounds pretty crummy and distorted at those levels.

Low listening levels beget lower listening habits? Don't let my missus hear that! My life is hell already! It already feels like I listen to music rather like someone who is sitting next to a passenger on the tube who is using earphones!

180dB is instant distruction of hearing in humans.
The loudest car stereo (in a contest) measured at 185dB.
Some say 194dB is the loudest 'sound', and higher is a shockwave, and is not a sound at that point, (like an atomic bomb or big explosion, the shockwave can be seen moving away)
150dB for a short time will give permanent damage to human hearing.
Blue whales can whistle at 188dB. I guess underwater is different than in air. And i would NOT want to be right next to a Blue whale singing.
Then some claim to have produced louder sounds. Nasa claims 214dB. (but that may be a calculation based on some other measurement?)
Then various volcanoes have been heard exploding thousands of miles away...
Football stadiums with fans yelling: loudest 127dB.
Jets taking off 140dB or so...
European standards in the workplace are:
85dB employers must offer ear protection. at 90dB the employee MUST wear earplugs, AND the employer has to try to reduce noise levels.
In the USA those levels are 5dB higher for the rules to apply
75/85dB chamber music group in small venue
100dB is a chain saw or pnumatic drill.
110 dance club'
120 rock concert, thunderclap, (though a rock concert can reach 150dB peak)
130 jet takeoff, gunshot
120/137 Symphonic music peak (IN the orchestra, probably right next to the trombones and trumpets which by themselves can reach 120+dB)
So I hope this helps.

Niacin: you should try a good headphones setup. Then for when you want LOUD, you can use the phones.
I use headphones at night if I want to hear Rock..
And your wife will(almost certainly) have better hearing than you anyway.. it is a fact women have better hearing than men by a big margin, on average.
(Google it before you scorch me with flaming responses!)

I listen to music around 80db with peaks to 90db with a Radio Shack SPL meter. Obviously I can turn it up higher if really in the mood to rock, however the best part of a great music passage is the silence inbetween the riffs. The dynamic range and level of a recording has plenty to do with what level sounds good to the listener. Most of the rap is recordeed at the full range capable so all the music and lyrics are at the same volume level. This is just as bad a compressed music MP3 etc.
For me it is about the sound quality. The experience of the music. Volume takes second chair.