Michael,
The D50 is a stripped down version of the D70. Two years from now the difference in price will be forgotten and you will have a fantastic DSLR and 1,000's of captures you will like.
My advice, get the $300 Nikon 28-200mm G...compact, and very sharpe. You will be able to get tight head shots easily without being in your model's face.
Here is Orchid at almost 200mm:
Jim