My question is mostly directed about the impact on search engines, not about clickthrough ratios, etc. although I appreciate the comments. I've decided to potentially offer a submenu on the top horizontal area instead of optionally placing it on the side, which may not be as obvious. Some say it's fine there but let's say the submenu seemed like a good offering. The issue is whether all those links placed before content will have an effect on SEO. I have seen repeatedly discussions about how having your most important content up at the top as high as possible is most important. Having this many links above the main content is a big question mark - and that's the question here:

Q: Since a submenu will have at least 70+ links in it, is it an SEO liability if it is placed before the main content on a page loads?

I have an ecommerce shop here: http://m00.biz/UHuGGC

I've added a submenu for each major category and subcategory of items for sale. There are over 60 categories on that submenu. I've heard that loading this (and the number of links) before the content is very bad for SEO. Some will place the menu below the content and use absolute positioning to put the menu where it currently is now. It's a bit ridiculous in doing things backwards and wondering if search engines really don't understand. So the question is twofold:

(1) Are the links better in a bottom loading sidemenu where they are now?

(2) Given the number of links (about 80 in total with all categories and subcategories), is it bad to have the sidemenu show the subcategories which, in this instance, are somewhat important? Should I just go for the drilldown, e.g. show only categories and then show subcategories after?

Truth is that users probably would prefer the dropdown with all the categories and second level subcategories, despite the link number and placement.