He wants something between 20 and 25 percent, according to this interview he gave to Maria Bartiromo (about two minutes in). This will do wonders for the stock market (and the mid-to-high end real estate market, for that matter).
Obama offers assurances from Warren Buffett that a 33% or 67% increase in the capital gains rate will not distort market decisions. Buffet would know about market distortions. He built much of his financial empire on exploiting the distortions created by the death tax — buying up life insurance companies (worth much less without the tax) and family-owned businesses with tax-motivated sellers.