Guild Wars 2

I’m mainly PvE and I use Sword / Warhorn often, with Rifle offset. It seems like higher damage with better survivability than with a Sword/Shield, or Greatsword.

What are the community’s suggestion(s) for best warrior weapons / weapon combos?

And where do I spend Karma for great gear @ 80?

Greatsword and rifle in my opinion.

As for the karma gear you will have to check the karma vendors in Straits of Devastation, Malchor’s Leap, Cursed Shore.
I’d recommend checking out http://dulfy.net/2012/09/08/gw2-templegod-karma-armor-sets/ for the stats you want and the exact places you can get them.