I recently decided that I wanted to try a taste of the BYOAC lifestyle without too much commitment and thought that building a single player cp that I could use with my laptop or desktop computer would be a good way to start.
Because I wanted to use the controller w/ my laptop computer, USB was a must.  Because I am an impatient (and cheap) S.O.B. I wanted to order from a vendor in the U.S. to cut down on shipping time and cost.  These constraints landed me with a GPwiz eco from 
www.GroovyGameGear.com I have only good things to say about the service and products that Randy provides, the day I ordered (Thursday) I had second thoughts, emailed Randy to change my order, had third thoughts, emailed him to change it back, and asked 2 or 3 questions about which software I would want to use with the GPwiz.  If I were a vendor I would be sick of myself as a customer, but Randy's service was great in spite of me.  I think that I finally made up my mind at about 2pm pacific time (Randy's in NY) and still managed to recieve the parts on Tuesday (Monday was a Postal holiday.)
When the parts arrived I immediatly made a shoebox cp (did I mention that I'm impatient?)  I didn't have any wire at home so it wasn't functional, but it gave me a feel for the layout.  When I had some free time at work the next day I drew up a layout in AutoCAD and printed it fullsize.  After hours at work I quickly whipped up a little box, drilled holes, mounted my equipment, and wired it all up.  When I got home the software part of the setup was easy (as far as the controller went) and I started playing.
Having a friend from out of town staying with me, I realized that now that I was sure I liked having arcade controls I needed to make a 2 player CP... but most of the time I would be playing alone, and usually with the controls sitting on my lap.  I had to make a seperate cp for player 2.  
This is where I am.  A 1 player cp with grand plans (not really grand, just new (I think))  I am going to use DB25 connectors on the two control boxes and set it up so I can either connect them by clipping them together with the connectors mating or use a m-f DB25 cable to connect the units for use with the cp on the players laps.  This way I can use some more of the (plentiful) inputs on my GPwiz for player 2 and not have to buy another interface.  This solution also avoids wasting anything when I move all the parts into an upright cabinet.
Here are the pictures of where I am now.  I also have a thread in the artwork forum for my 2-part cp art if anybody is interested in helping. 
http://forum.arcadecontrols.com/index.php?topic=63792.0

This is what the wiring job looked like for the initial test run.

And this is after cleaning it up.

Thanks for looking, feel free to comment (good or bad) I love praise almost as much as a good fight  

Later,
Brian