My main concern was really driven by depreciation and this is an opinion only and may not hold up over time: I have concerns, based on Pontiac's demise, about the ability of these cars to hold their value and I wouldn't even pull the trigger on the GT until I got the right number. I bought an untitled demo (5,000 miles) from Beck & Masten at a greatly reduced price which (when combined with the 0% interest) should go a long way towards mitigating a significant drop in market value. Because there are so many fewer GXP's (about 50 GXP's in the large Texas markets compared to over 400 GT's for the same market) I simply could not secure a significant enough discount. When you combined that with my "guess" that gas prices could be very high again soon and the elevated insurance costs, I bought a GT. For me it was just a better choice for a "daily driver".
Now, if at the time the next model years are released, there are any unsold 09 GXP's; you maybe able to get the same kind of deal on one that I just got on the GT.