What are you favorite boss fights? Here's one example:

But by far it has to be Mr. Aran, the fact that he has low armor and only one AoE makes it the best melee oriented fight in kara. BTW, if you enjoy Pre-BC fights more; you can also state which ones and why

Why is no one talking about trying to down the 25 man instance boss Magtheridon yet?

Well as someone from the very well known Death and Taxes guild says, they tried him a few times and got owned. Either he is too gear dependant (i.e. you need phat epix lewtz to kill him), or Blizzard haven't finished tuning him yet.

Seems there is a big chest beside the boss that anyone can walk up to and loot/ninja!

Yup, the very last boss of Hellfire Ramparts seems to be an open invitation to ninja-ing that loot. Just like the Cache of the Firelord (another notorious ninja location), a chest spawns after the boss dies, and anyone in the group can step on over, open it up, and grab everything in it. Pookybear (nice name) has noticed this too, and Blue answers: It probably won't happen.