2-3%.
But I'd hold out for a 0% offer
0% means you don't get the rebates, and its best to take the rebate money. Not to mention there is absolutely no such thing as a 0% interest rate. It may be advertised as 0% but you can bet your arse the interest is going to be made up in other BS fees.
If rebates were always the better deal, that's all they'd offer. For expensive cars, the 0% can be a much better deal than the rebates.
Also, not all dealerships offer in-house financing anymore. My brother is a car salesman and they just have a list of lenders that they use for trying to get buyers financed. Of course, if it's a new car, your best bet is probably to get one of the manufactuer-subsidized low rates.
As some other guy said, I think 0-3 percent is good for new cars, and 2-5 percent is good for used cars. Anything higher than 5 percent means you should look somewhere else or your credit is questionable.