So for the past few days, maybe week, my 360 hasn't turned all the way off.  After I turn it off I can still hear it running as if it were finishing a download or something.  The lights are off but it's still generating heat.  I put my hand back behind and it's not hot enough to be concerned about, it just bothers me that it stays on and I can hear it when the TV is quiet so I unplugged it last night.

Is there some setting I accidently turned on to make it stay on like that?

Also I've noticed that about half the time I turn it on it doesn't auto-sign into my account and not quite sure why that is.

Do you have anything connected to the 360?

When my Son leaves his controller plugged into his Old 360 you can he a sound like the fans are running, when he unplugs the cord from USB it goes away.

I have exactly the same problem, never did find out the cause!

well, like sega4life said if you have something plugged in that could be why. My launch 360 was like that. If I had my controller plugged in it wouldnt turn off.

Also, if you are downloading something it will do that, but I can't imagine something taking over a week to download.

Mines does this too.

After a few seconds it turns off but I always wondered why it did that.

At one point I had my PS3 controller plugged into it to charge the controller but nothing is currently plugged into it.

It's a pain but I just take out the power cable and insert it back in after. I remember now I think someone said it's something to do with the Xbox not remembering to turn off properly? something inside not working correctly ...

I unplugged it yesterday, I just haven't gotten around to plugging it back in.  I suppose I'll know tonight since my copy of SSFIV should come today and I'll be playing it. 

Changing tactics are you now twesterm? Trolling the 360 instead of the PS3? Much safer I must say.

I never noticed because I just turn it off and unplug the brick to outlet cable. It happens usually when something USB it on, it'll be green if it does but appear off.