Due to a variety of reasons, one of which is a visual impairment, I still browse at 800x600 resolution. Even though I'm probably in the vast minority, I'm sure a few others still use 800x600 as well.
I've noticed several issues while in 800x600 resolution:
(1) The biggest one is that the "new posts" option is now totally not visible from the navbar. Even if the text wraps around or we see a "^" option, there needs to be a way to get to this link without changing the resolution. I'm sure this applies to other site links as well, but the "what's new" is what I (and many others) use most so this needs to be accessible by everyone.
(2) I noticed the sidebar now is below the forum list (on the forum home) and below the member list (on the members section). I'm assuming this is due to the responsive design and can easily be fixed in the admin cp.
If you notice any 800x600 browser issues, please post them here for those who might be interested in following this discussion.