I happen to also have a Jeep Liberty as well... Interesting that you were deciding between the Liberty and the GTP.

Have you considered the Grand Prix GXP? It's basically an uplevel GTP with a 5.3 Litre V8 I think it's supposed to be out in the spring... The GTO is another nice car, with a much nicer interior than the Grand Prix.

Have you changed the oil in the liberty yet? It's the biggest pain of any car I've ever had. The oil filter is mounted above the skid plate, so you have to stretch and reach around to get it. In fact, unless you know where it's exact location is, when you get under the car for the first time, I can gaurantee you won't even be able to find the oil filter.