I'm too lazy to do much. So I just diversify across different indexes, domestic/international, fixed income/stock indexes. Don't think most people can consistently predict where things are going every single time. Also, your tailor your mix based on your age. I also have a short term trading account mainly for speculation, but it's just play money.
I'm in the early thirties. I recently changed the mix from about 95% stock+indexes to 85%, and will continue to do so as I get older and as the market conditions persist. Also, I went from about 75%/25% between domestic and international to about 65%/35% split. One of my most favorite funds has been VGPMX, but unfortunately is closed to most new investors