Rene' Villela , Oct 07, 2008; 10:16 p.m.
1) Different settings for different occasions. I would say ISO AUTO, picture mode STD, D-Lighting OFF, Noise reduction OFF (you should do that on your computer).
2) To start maybe RAW + JPG. You should try Nikon Capture NX2, it will come with your camera (60 days trial). Work on your shots with NX and then save what you need in JPGS otherwise the TIFF files are really large and will eat up your hard disk. As you get better working with your software maybe just RAW will do.
3) Sorry! I don't shoot action.
4) White Balance AUTO. It works really well on a D300. You can just tickle it a bit on NX if you are not happy with the results.
Good luck! and enjoy it!