sony vx2000 = arguably most popular skate video camera out there, cheap and good low light
sony pd150 = vx2000 but with xlr inputs
sony pd170 = slightly bigger than the pd150 not too many major changes as far as I know
panasonic hpx170 = the new smaller cheaper hvx200 does all the same stuff but has no tape deck saving space, weight, and price, but then you can only shoot p2.
I would totally go with the hpx170 it seems like the best bet for you. Don't go standard def if you can afford an HD + 24p camera trust me, I'm glad I didn't. Plus you can always shoot SD on an HD cam, and who knows you won't always be shooting skate videos, the 170 is a great camera for the transition between amateur and prosumer/professional camerawork.
I've actually heard of a lot of skate filmers selling their vx2000s/vx2100s back to buy vx1000s. The vx2k does have extremely better low light, but the vx1k produces way richer colors in the day time. Not to mention that the vx1's fisheye is wider than the vx2k's
I'm kinda leaning more toward the HVX200. I like it's weight for more fluid run/line shooting, and it's tape deck for back up. Is there any reason I should take the 170 over the 200?