According to Matt Cutts (head of Google’s Webspam team), “…there’s still a good reason to recommend keeping under a hundred links or so: the user experience. If you’re showing well over 100 links per page, you could be overwhelming your users and giving them a bad experience. A page might look good to you until you put on your “user hat” and see what it looks like to a new visitor.”
Although Google keeps talking about users’ experience, what can really hurt if they see way too many links on a page is its rankings. So, the rule is simple: the fewer links on a page, the fewer problems with its rankings.