Most still adhere to Vanguard's index-tracking roots – 78 out of the 88 ETFs follow benchmark indexes, with expense ratios as low as 0.03%. Even within this category, there's remarkable variety.

GAPE CANAVERAL, Fla., Dec. 6--The Vanguard test rocket--with U.S. hopes for some recaptured prestige aboard--barely struggled off the ground today, then fell back and exploded. Although there are ...