Sad/Depressed/Upset - The one and only time I will listen to Staind for more than 1 song at a time. Depending on the type of sad, Dashboard Confessional too. Aeris' theme (orchestral) from FFVII

Angry - NIN, Slipknot, NMS04, anything with power behind it. Savior Sephiroth from FFVII

There are a lot of bands I'll listen to whenever anyway.

I'll also play some of my stuff on my keyboard. I'll do this all the time anyway, and I have stuff to fit whatever mood.