Just been playing the Saints Row Demo from Marketplace and after posting this I am going to put in a pre-order down because it is one very nice game. Saints Row is a blatant GTA rip-off, but I don't care because it is so much better. The combat is done really well and without a gun lock-on mode anywhere in sight.
The last GTA game I properly played was GTA3 which I had for the PC. The one thing I hated about it more than anything was the stupid floaty boat cars which would always rock from side to side on the road because the car suspension was simulated so badly. It was like all the cars floated on a cushion of air. The cars in Saints Row however drive very well indeed and feel great. The game has a GPS mapping system so you can always get to your destination quickly and in the full game you will be able to customise and properly pimp-up cars. Even get them rescued if your baby blows up.