I made the decision that another poster suggested: I went for the new 2009 RX with discounts (see posts above). To my knowledge, the discounts ("marketing support") ended Mon Feb 2nd, and new discounts have not been announced. The feeling among the dealers I spoke to is that they will be continued at the same level (i.e. $5000 per), with dealers still giving 'invice' pricing, i.e. some 9-10K $ 'off' MSRP. But you need to check what the 'new' program will be. As yet, it seems not to have been announced. IMHO, if another 'support' program is announced, you should lock in a purchase of a new RX.
I'd say go for the brand new one as it has some good discounts. I don't know the new incentive for Feb but don't think it's less than Jan. I got mine for 10K less than MSRP and very happy with car :)
Thanks.