Rafterman
No longer a newbie, moving up!
I will gladly go for the d7100
Don't rule out the D7000 either. The D7100 is $1,200 for the body alone, while the D7000 can be picked up for $900 new or $750 refurbished (what I bought). I don't know what your budget is, but even if you buy a new D7000, that gives you $300 extra to put towards a nice lens over the D7100. IMHO, the D7000 would be fine to shoot skateboarding, snowboarding or surfing. The lenses you buy will better determine what you can shoot effectively. As mentioned above, something wider would be better for skateboarding, while surfing will require some reach (at least 200-300mm I'd say). The D300s is a great camera to be sure, but keep some other options open, because pretty much anyone here will tell you that quality glass is the most important thing, not the body.