1)Known differences between the D70 and D70s; D70s has a cable release, 2inch LCD screen (1.8 on the D70), larger battery capacity (needed due to the larger LCD screen), Newer firmware (newest D70 firmware update will give you the same features). The price diff between the two was $200 at one time....for $50, it's probably worth it. 2) D50; Pros...Less $ Cons...feature limited compared to the D70s (eg top end shutter speed, etc), SD card, kit lens is not very high quality 3) D200...very very limited supply, in fact some are paying more than list price just to get it. Expect to pay around $1700 to $2000 for the body right now. Metal construction, better sealing against dust, etc. Loads of yummy features. Note that some "banding" issues have been reported in early production D200's...it may be best to wait until that is sorted out.

In youth, we learn....with age, we understand.