Choose the most used one from each category

Music Files
1. mp3(128kbps)
2. mp3(192kbps)
3. mp3(256kbps)
4. m4a(256kbps)
5. mp3(320kbps)
6. 16bit lossless (as good as CD)
7. 24bit lossless (as good as Vinyl)
8. CD
9. Vinyl

Players
1. Desktop computer
2. Tablet computer
3. Notebook/Netbook
4. Smartphone
5. Other portable player (iPod Touch, iPod Nano, etc)
6. CD player (portable)
7. CD player (unportable)
8. Turntable/Phonograph

Receivers
1. Headphone
2. Earphone
3. Speaker

m4a 320kbps

my macbook

headphones

EDIT: You realize m4a is available in 128, 192 and 320 right?

Receivers:
Ears

File quality depends.. I usually keep it around 256. MP3/M4A

Music Files
5. mp3 (320kbps)

Players
1. Desktop computer
2. Tablet computer

Receivers
2. Earphone

320 mp3, Duh

I cant stand it when people listen to 128 with their cheap ass headphones

Depends

Most of the time earphones via my iPhone or Mac. When I'm home alone tho, out comes the surround sound and the walls start to bop with me

256kbps
computer/phone
headphones

320, on my Mac, using speakers.

But I also like to play jazz, classical, and house vinyl records on a turntable with speakers.

Music Files
mp3(320kbps)
Vinyl

Players
Desktop computer
Other portable player (iPod Touch, iPod Nano, etc)
Turntable/Phonograph

Receivers
Earphone
Speaker

m4a for music that I purchase or that iTunes Match picks up. Highest quality available mp3 for everything else.
95% of my listening happens on my smarthphone, 5% on the laptop at work.
I use headphones at work, earphones outside, and speakers at home

Yeah but I didn't know people actually use them. Sorry.

16-bit, either from CDs or... you know...

mp3 or m4a. I refuse to listen to anything below 256 kbps though.
Mac or iPod.
Headphones.

Always get the iTunes version (one way or another ) or 320.

Macbook Pro (Can't wait until I switch from my 13" MBP to my 15 inch one. I don't get how people listen to anything out loud on the ****** 13's speakers

Earpods/Computer speakers with sub woofer.

CD, computer, phone, iPod

CD
Smartphone
Headphones

Headphones

Lady Gaga's discography at 24bit/96khz, Vinyl quality.

The other songs/albums in mp3

Mostly 256 kbps m4a on my iPod, or CD on my speaker system.