A discussion at Cre8asite Forums goes into a lot of questions about what a search engine prefers to see in a homepage. Is dynamic content preferred, or does a static homepage do just as well? For instance, the big contenders (eBay, Amazon, CNN) are updating their homepages constantly. Should we follow their example?
As Bill Slawksi says, it varies per site. A hybrid of dynamic and static features may be the best solution for most. Too much dynamic content may lose a familiar feel to a regular user.
Old stuff that doesn't change too much or too frequently that gives people a feel for the personality of the site, and a glimpse of what makes them unique while providing some stability.
But it really depends who your competitors are, according to Pittbug. If you're challenging these big sites, then sure, you'll want to emulate them as much as possible.
Ruud, however, says that search engines don't take preference over any particular homepage presentation. It all depends on your business.
Finally, EGOL says that you can view your analytics and see what kind of activity your users are doing on your website to see if it necessitates change.
An interesting read indeed. I personally like some dynamic elements. It makes the site feel like it's being attended to more often.
Forum discussion continues at Cre8asite Forums.