Gran Turismo is the best in terms of realism and racing simulation but for high adreneline, Need for Speed is tops! I like NFS better because the controls are a bit easier and control of the car is much more managable. In other words, where it takes lots of practice to get decent in Gran Turismo, you're up and cranking on NFS in no time!Need for Speed is so totally addictive it's unbelievable. I can literally play it for hours and have. The cars go wicked fast and it's fun to outrun cops, dodge barracades, do jumps while driving at high speeds. I haven't tried Underground yet but if it really is better like everyone says, I'll be looking forward to it coming down to the Greatest Hits collection (I NEVER buy games over $20)!