New Rider

Looking for some help here. I'm looking for a good bike for trails/street riding. I'm 6' feet tall and weight approx 200 pounds. I'm looking for a good starter bike, doesn't have to be necessarily new or anything but a good one for a beginning for fun. I was looking into some 250cc ranges but I have no clue. Thanks for the help

1) your physical size (6'0" - 200 pounds)
2) How physical / aggressive are you ? average
3) what do you plan to ride- woods, fields with friends
4) Do you have any riding experience? not really. Mini choppers and mopeds
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)? Whichever
8) Do you have a dealer close by your home that you might use and what brand(s) does he carry? yes, all kinds
9) How much ($) do you plan to spend on a bike? Like to go used since it'll be my first bike before spending a lot
10) Do you live in California? no
11) Your age? 28
12) anything else that you think would help form an opinion
I'm just looking for something that is functional but yet I can upgrade as well. Will use strickly for woods or fields

Great. Thanks