Rich keep in mind that the burst rate is only decreased when shooting in 14bit raw. you can change the setting back to a 12bit raw format and retain the full shooting speed on the d300.
EMS personally i would go with the d300. If you are just starting out with a new system do A LOT of reseach. there are a couple really good sites to review the camera bodies and lens. for me the lens options on both systems are very good and very comparable, but for me the big difference is the nikon is much more user friendly. changing settings is a lot easier and there is a lot less scrolling through menus, plus if you ever get into the lighting systems nikon's is WAY better.
previous to the d300 nikon was critisesed for it's excess noise at high ISO. with the new cmos sensor that has been amazingly improved.
i love nikon, but it may not be for you. do your research and try to think of what kind of shooting you will be doing the most and then see which overall system suites you best.
also keep in mind that the d300 does not come with user friendly auto presets on it so if you dont have a clue about photography beware that it will take a bit of tinkering getting used to it. it demands a bit more overall knowledge, because you cant just turn a dail to the little man that looks like he is running when you need to shoot sports. rather you have to know what settings you need and set them in.
www.dpreview.com - great for body information
www.fredmiranda.com - great for lens and body reviews