"Look at the stock market on a 12- to 18-month time horizon," Katz advised. "Turn down the volume on the day-to-day volatility and scares."
"Investors will make most of their money in a bear market," Millen said. "It's just hard to see it right now."
Millen recommends Danaher and Praxair.
"These companies have common characteristics," he said. "They have durable competitive advantages; they have returns consistently above their capital costs, and they're each very well positioned to the infrastructure build-out in the developing world."
Katz likes the prospects for technology's stars.
"Technology is taking quite a beating of late," he said. "We think things like Dell and Cisco, Microsoft, Novellus, are great prices here."
Katz is also fond of "old economy" businesses.
"We think General Electric is a great company, at a very compelling valuation, pays a nice yield while you're waiting," he said. "When you have a quality business at 13 or 14 times earnings, you're going to make money."
GE is the parent company of CNBC.com.
Millen and his family own Danaher and Praxair, and Katz, his family and his firm own Dell, Cisco, Microsoft, Novellus, and GE.