I currently have this ergonomic mesh wizbang thing with a lumbar support, adjustable arms etc and it's killing my back and arms. Looking for suggestions on a nice comfortable gaming type chair that reclines, preferably with adjustable armrests that aren't hard rubber like what I've got now.

I just bought a Serta office chair.  But I'd recommend sitting on some first.  I went to Office Depot and probably sat on 10 or so before I found one I liked.  I'm also 6'5" and 270 pounds...

I've never seen a worthy office chair at Office Depot, Staples, Office Max, etc.  

You need to be well-up over $1k to get a good one.  Prices that those stores don't like to carry.  

I'm using this one: alera elusion with the headrest linked on the amazon page. It's very comfortable and hasn't caused me any issues. It's about the only decent one in the sub $300 price point that I could find through a lot of research. It reclines a bit, arms are adjustable and tilts back. It has decent lumar support and the build quality seems pretty good. The optional headrest isn't too much extra and while it is third party it does bolt right on. I put more hours than I care to admit into gaming on my weekends and have had no issues with my back even though I'm pretty susceptible to back pain due to a lot of mistakes in the gym over the years.

I'll save you a ton of research and just mention that the herman miller aeron chairs are generally the go to, but they're pretty close to $1k. They can be had used for $500 if you look around. They last forever so I wouldn't worry about buying used.

Steer way clear of "gaming" chairs. A race seat bucket is about the least comfortable thing you could possibly sit on and while I generally steer clear of "I'm right and everybody else is wrong" statements I'll make an exception. They're usually cheap Chinese junk with some awful colors and people keep recommending them because they know they blew their money on more bullshit marketed to gamers and they're trying to justify their purchase by lying to themselves and others.

I bought this This (Amazon link) two months ago. I sit in it for about 8 hours a day during the week and several hours a day on the weekend. 

I'm happy with it and the negative reviews have yet to line up with my experiences with it. It's comfortable, the controls work, and the support is great. 

Good luck on the hunt!!