what kinda of bike?

[dirty_mango]

1) your physical size (both height and weight are important)
6 feet and about 170 lbs
2) How physical / aggressive are you ?
Pretty physical
3) what do you plan to ride- MX/SX tracks, woods, fields with friends or ?????
woods, or the desert with friends
4) Do you have any riding experience?
Very little
5) Do you think you will race ?
No
6) Are you mechanically inclined and will you be doing your own bike work?
yes
7) Do YOU have a preferance to a brand/ motor choice (2 or 4 stroke)?
No
8) Do you have a dealer close by your home that you might use and what brand(s) does he carry?
9) How much ($) do you plan to spend on a bike?
up to 5.5k but would rather spend less
10) Do you live in California?
I live in Arizona
11) Your age?
19

 

[zig06]

Because of your size, and the fact that your running in the desert, a stock yet big gas tank would be a plus (or something that got good mileage).

Here's my suggestion in no particular order:
KDX-200 or 220
XR-250
DRZ-250

With some reservation, I will consider recommending a "modern" 250f, as long as your aware that these are more race bikes and less trail bikes. And as a result, the maintenance will go up.

WR-250
CR-250F