This is my level 80 Unholy Death Knight soloing Onyxia. It's not the cleanest kill, but I did this more to inspire others to go after other old world bosses as I find this really enjoyable.

Armory Link: http://www.wowarmory.com/character-sheet.xml?r=Area+52&n=Daighe

I was in a mix of blues and greens at the time.

Enjoy!.