The Google cache, by inserting its own HTML, disrupts absolutely positioned divs on the page.
I am using templates for a site which has a fair number of content rich pages.
You might try assigning a z-index value to the layers at the top of your pages. Even layers that are set using position:absolute. I've done this in the past and was able to ensure my page layers display ON-TOP of the Google/Cache Box instead of the other way around.
In any case, I don't sweat it... it IS only a cached page after all. I imagine before long Google will adapt their code to accomodate CSS-P.
I've actually got divs sitting on top of a tabled-out template, but a thought (a la papabaer) occurred later on that wrapping everything in the template in a div might solve the problem (until I can get around to making the template non-table).
As far as not bothering about the cache goes, I was struck by Brett's comment a year ago about how many people might just hit the back button when they see a broken layout.