The song thats usually ringing in my head is "Murhaaja soittaa pasuunaa" or "The murderer plays the trombone" in english. It is a song by my favourite band Y.U.P.
http://www.youtube.com/watch?v=AlSiZzLBwc8&feature=related

http://www.youtube.com/watch?v=2deLtoiFuJw
^been stuck for the past three days

http://www.youtube.com/watch?v=G7oGx2dImE8 I can't get this <censored> song out of my head. I need therapy.

Skazi - I Wish
Heard it this morning, and its been stuck in my head ever since. :/
Its a great track, by the way.
http://www.youtube.com/watch?v=PIL2ttBqTsM

3 new ones:
Down From The Sky (Trivium)
New York City (Emigrate, which is the lead guitarist from Rammstein's side project)
Determined (Mudvayne)

Usually, when I get a song stuck in my head, I can't wait to get rid of it.
Happily, "Rain Man" by Black Stone Cherry has been a recent exception. :)

I personally prefer the unremixed version by Infected Mushroom.

Awesome song...The lead guitarist and vocals was heavily influenced by Metallica. =)
http://www.youtube.com/watch?v=EApnhO2OIrw
And this song just sounds awesome and is catchy....
http://www.youtube.com/watch?v=ZUB5rA8EdXg

I love this song, but it's annoyingly stuck in my head.

I saw the title and exited out ASAP...you bastard.

Svennebanan by Promoe
...can't get tired of this beat even if it is stuck in my head for eternity.

Finally got rid of Skazi's song... :) But too bad another one is now stuck in my head. I've been singing it all day (not that there is much to sing, but still :))
Daren Styless - You're My Angel
[url=]http://www.youtube.com/watch?v=GZlTefhpIls[/url]

http://www.youtube.com/watch?v=POzqApVndeI&amp;feature=related ;)

http://www.youtube.com/watch?v=4WgT9gy4zQA
This gets stuck in my head all the damn time!