Reg gas is at $3.10 here in PA. If it hits $3.50, they'll be a push for hybrids so fast they won't have enough to sell. The car industry cannot respond fast enough to changes in gas prices.
In low gas price times, many will opt for a Camry LE which sells for about $19k these days, where the Prius II is about $21k. Camry has more power and seats 5 adults better than Prius. Gas prices are the great equalizer, and Prius is ready to take no prisoners as they go up. Oil may hit $100 / barrell in Jan. '11 IIRC. Great time to buy a new Prius.
dealers here are discounting $2K on top of rebates without batting an eye, i suspect you'll see some heavier incentives by January with the MPV and plg-in on the horizon