Voice quality is a major thing I listen for - I'm a voice major in college so it's hard not to critique things because I hear so much. It makes me mad sometimes because I can't just sit back and enjoy music - I always find something to whine about. They have to have good vowels and a good style - not to breathy not too forced. They have to have great diction - it drives me crazy when people sing and go "Tha chu" instead of "that you." (You might think I'm making it up but a lot of people sing that because they aren't aware - Phil Collins (musical genuis in my mind) in You'll Be in my Heart does it. Aly and AJ in their song Rush do it...and more. Not saying they're bad because of it because I listen to both Phil Collins and Aly and AJ despite that - but it drives me nuts when I hear it lol)
I have a guitar fetish as well - if they have nice guitar parts I love it :D lol
I like songs that tell stories as well. Billy Joel is my favourite singer of all time - one of the reasons being that every single one of his songs tells a different story. It's not all about love or sex like a lot of music is. And even if it is about love he tells it in such a unique way that I love it!
The song has to have good lyrics too (if it's something I understand - english - i listen to many foreign language songs and considering that i can't speak the language I don't know if the lyrics are good or not but oh well)

Edit: I also LOVE harmony - harmony is a major 'turnon' in music for me - if it has great harmony - i'm bound to love it lol

the first time, ill listen to the music/remedy.
the second time around, ill listen to their voice.
the third time around, ill listen carefully about their lyrics.
the forth time around, ill listen to all of them at once along with my feelings =)

i listen for a catchy beat or moving lyrics.

or catchy lyrics lol.

most of the time if i get something stuck in my head, kinda like on repeat, i know i like the song.

i listen for good lyrics XD like something romantic or sad

I usually like a song for lyrics but there are times when I get into a song because the beat is good and catchy as well.

It depends with each song, for me anyway (: . Like if it starts off with a guitar solo or really strong guitar, then I pay more attention to guitar throughout the song. But more than anything, it's lyrics <333. Although, sometimes, I can't tell what they're saying o.x . Like when I first started listening to screamo, I was so lost D: . A catchy line really helps me to remember the song though :3. Like I'll remember that one line, and type it in Google and add the word 'lyrics' after the line and I'll re-discover the song :D.

Usually its the beat and rhythm for me. After that its the combination of instruments used and whether it all sounds good together, and that includes voice. After that if it has singing in it I then listen for words and lyrics if I understand the language.

I observe music I like alot. I usually observe to learn from it and use these new learned things. These things usually end up in observation of good combinations. Like how drums and basslines work together. Or how a different pattern in the hihats unnoticably gives more variation to the song.

I've learned that many things that easily go unnoticed in songs give that little more variation that doesnt make the song sound boring or powerless. For example, I like Daft Punk alot, though they barely use any of these techniques, and become repetitive in many of their songs.

Heh, Ill stop my rambling. Plot of this post: I observe lots of things when I listen to music^-^

I listen for a lot of different things in music. Usually what moves me the most is good guitar, to be completely frank. The moments I remember thrilling me the most are the ones where the guitarist just has a really powerful riff. I don't go for the super-flashy, technical showoffs at all, though. Those are an instant blegh. When you can feel the emotion simply through the notes of the music-- that's when it makes those butterflies in my stomach. I also like good or at least decent lyrics. A clever turn of phrase is always to my liking. I usually can't stand vulgar lyrics. There are several songs on the radio right now that have good melodies and whatnot, but I can't stand them just because the lyrics are so gross! I didn't think I was a prude until those songs got on the radio. o. o;; I also like to listen for good bass lines, unique drums... and vocals! I do love me a good vocalist. I also like to avoid repetitive things, or simplistic things. Not to say that those don't have their place as well, but I'd just as soon not have to hear the same thing over and over, or have to listen to something my fifteen year old brother could've written.

<3 /endramble

I usually look for fun and/or unusual lyrics in a song with a good beat. Soooo kinda both I guess. :)

I listen to the beat first, since I'm a DJ its just automatic. Then I listen to the lyrics. It doesn't have to be good quality, if the lyrics are good and the beat is passable then its ok.

I listen to Lyrics and the sound of the voice. I really care about thought provoking lyrics because I'm always trying to get inspired. I also appreciate a deep resonating voice way more than those high pitched choppy voices that are so common in the alternative bands I hear. It makes them all sound the same.