EMP, run up behind him, unload into the back of his head with a shotgun, run away when he comes out of it, repeat. He didn't even touch me.

Save up wall mines -- it takes about 4 or 5 (maybe less) of them to kill him. You just throw them down and he walks right into them...easy!

hes easy, only took two clips of assalt rifle ammo and two emp grenades

Much prefer my method of killing him by fire extinguisher.

I shot him until he died. Can't really member using any specific strategy. Other than not being near him.

Remote explosives were key for me. A couple of potshots with the pistol, two remotes, and dead. I barely survived myself (more EMPs would have helped), but it worked.

I beat the first boss on the hardest difficulty in like 10 seconds.
 
Save the mines you get from the walls leading to the helipad before the FEMA base.  With those 4, you can use them like grenades and throw them at his feet.  If you have a rocket launcher(I found one in the FEMA base), after the 4 mines, it only takes 1 rocket to kill him.

Typhoon Augmentation Second Level I killed Namir in two hits.

I fully upgraded the typhoon augmentation and it only took me two typhoon shots. It was so awesome :D

 @Liber:
 
I got irritated and turned the difficulty down.  Also, get a stun gun and emp grenades.  Further, it might help to scavenge the entire level before you face him for supplies.