Loren Cordain's latest paper deals with the beneficial effects of lowering LDL ("bad") cholesterol. The paper discusses how getting LDL in the range of 30 to 70 is optimal for cardiovascular health.
Getting LDL cholesterol that low is a pretty tough assignment. Mine was 90 when I had it checked in the spring. I've found one person, Mike Adams, who writes about having an LDL of 67. His site is here, and it's pretty interesting. His diet is extremely strict, and he exercises a good bit. As with most things in life, there are no shortcuts if you want real long-lasting results.