Couple quick questions... Wood etc..

[chrisindfw]

3/4" or 5/8"

[crashwg]

1)it's realy up to you, most "real" arcade machines are 3/4" though
2)MDF
3)Not quite sure how to answer this question without sounding like being a smartass... it's usually as simple as attaching hinges and a locking mechanism to a piece of material the size of your opening

[NoOne=NBA=]

3/4" or 5/8"  (I am using T-Molding)

I'd go 3/4" for a full size.
If you use 5/8" on anything other than a bartop, it will look too small.

MDF or Particle Board

MDF is better than particle board for almost any application.
It is nicer to work with, and doesn't fall apart like particle board.
I personally used plywood because it holds up even better than MDF.

Whats the best way to create the door for the back panel?

I used 1/4" plywood for all the non-essential pieces on mine (top/back/speaker housing/etc...).

[RecycledPast]

1)

[shmokes]

If you are painting use MDF.  If you are laminating (highly recommended if you have the money.  Easy and superior looking) use plywood.  Don't use particle board or MDF if you don't have to.  Both are very heavy and paritcle board falls apart.  Even industrial strength particle board will not hold up like plywood (I could be wrong on that) and it's WAY heavier.

A single 8' by 4' sheet of MDF weighs upwards of 1 million pounds.