Do not, and I repeat, do NOT go for a leather office chair if you plan on being at your computer for longer than 40 minutes at a time. It doesn't dissipate heat well, so your body heat will gradually warm your chair up to uncomfortable (sweating) status after extended periods in it.
Also, pleather/leather will wear out far faster than something like mesh.
At all costs, pick something that has a good quality mesh back, and also, if possible, one that has a mesh seat.
Another thing is that in regards towards looking at chairs, branding generally does tend to lead to better quality office chairs. Better warranty, build. There are exceptions if you go the OEM route for some of the major brands, but you don't get their warranty.
My recommendation would be this: Eurotech Apollo with headrest (since you are fairly tall, all things considered). Its a full back + headrest. And if you are wondering about that price and that seller, I've personally ordered three from them for friends and family, and they are quite legitimate. And they have the lowest price out of pretty much everywhere (spent a LONG time searching for a chair).
Solid build quality, a ridiculous amount of adjustment options (Eurotech's specialty), and a lifetime warranty.