As do I. In fact, one of my favourite Firefox add-ons is called NoSquint, which remembers your zoom setting on a per-site basis. For me, Hacker News is constantly at 150%, and wikipedia is 180%.
As for the arrows being pixelated, rather than having higher resolution images, shouldn't the images be replaced with unicode?
After playing with the extension for a moment, there's one key feature that'll probably make me keep it installed: per-site configuration of text-zoom vs. full browser-zoom. Firefox's "Zoom Text Only" is a global setting, but the extension permits it on a per-site basis.
I think the answer to your question is yes, but at the risk of being downvoted, you might get a nasty reality check if you view source and do a find on the string "table."
I think sort of statement is pg's secret intention / reasoning behind keeping HN the same: hackers will make it work for themselves (e.g., via custom stylesheet etc.).
The problem with that reasoning is that it only applies to desktop. It's mobile where reading HN is painful, and that's exactly where I can't use custom stylesheets, at least not without installing a new browser.