I agree, 6A or 6K, since there's no one behind you, you actually get a little more storage space behind/next to your seat. And they're close to the washroom and snack bar. Plus from YYZ (at least) you have a separate boarding entrance from Y, but the Y entrance people also pass you if you're seats 7 to 11, so a lot more passenger traffic.

One thing I like way more about the 777s over 767s is the overhead compartment; 777s has way bigger compartments that you can put your carry-ons and others stuff up there. 767s you can't even put a wheeled carry-on on the window side!