Dude why don't you scoop up GT5P? Its still got 6 tracks more if you count the different course layouts and forward/reverse.
I'm excited for MGS 4 as well although I need to crack down on GTA4 this week.
From what I've heard most people were not impressed with the Haze demo that was out. I have not played it yet but watched the preview on G4 and it doesn't look that good IMO.
I'm currently playing GTA4 and GT5P. Hit me up AbsynthHaze is my PSN. I should be on for a bit this weekend racing online and a few team deathmatches .