Something that should be mentioned -- if you need to resort to X-UA-Compat, IE conditionals, or any of the rest of that nonsense on such a simple layout, there is probably something fundamentally flawed with how the page is built.
Though you have jquery in there, so that's a given.
You have a remarkably simple page with few real images -- and it comes out to a whopping 300k in 18 files... The HTML isn't too bad, if a bit non-semantic (like lists around non-lists and no lists around obvious lists?!?) but problems like the one you encounter are just a symptom of deeper rooted issues.
You're using a image replacement method that does NOT gracefully degrade images off -- defeating one of the entire reasons to USE image replacement. The way you have the menu images sliced up of COURSE it added gaps and/or showing bits of the wrong menu when zoomed. There is NO reason to be using five separate 22k files there for what should probably only be a single unified 50k jpeg. (that rock pattern would hide jpeg artifacting beautifully)
To show you what I mean, I took a few moments to rewrite your page using my Accordion script which doesn't rely on that jquery asshattery.... optimized the images, made the markup a bit more semantic, etc, etc...
as with all my examples, the directory
Index of /for_others/lunarBuffalo
So basically, same page in 2/3rds the bandwidth and little to no cross-browser issues... and it took me about fifteen, maybe twenty minutes because of the methods I chose for building it. Said methods involve no need for X-UA-Compat or IE conditionals in the markup -- again, if you have to resort to those, the methods you're using for building the site are probably flawed.
Of course, the biggest savings in files and sizes apart from kicking jquery and the lightbox nonsense to the curb came from this:
One image to rule them all. If you can slide them one direction, you can slide them both directions.
Hope this helps, or at least gets you thinking on different ways of building pages.