As much as I loved the Arcade Paradise 2 cabinet, playing on it for a couple of years brought to light a few changes that I wanted to implement.
The biggest change that I wanted to make was to move to a much bigger monitor. The 19" PC monitor that I was using just wasn't cutting it anymore, and it was the biggest, most obvious thing that kept the cabinet from appearing to be "arcade quality". I arduously weighed the pros and cons of using an arcade monitor versus using a television (see the Monitor Types review for an overview on the basic differences), and decided that a television suited my needs better.
On the topic of "arcade quality", the other overall thing that I wanted to accomplish was that I wanted this cabinet to be as close to "arcade quality" as I could possibly make it. I wanted to make a cabinet that made people ask "Wow, where did you buy this?", not "Hey, that's neat - how long did it take you to build this?" Obviously anyone who's into the MAME scene will recognize it as a MAME cabinet, but I wanted the "homebuilt" aspect of it to be completely transparent to the outside observer and gamer. Visual appearance and construction are parts of the whole "arcade quality" equation to me, but it also includes things like how seamlessly the software runs, how intuitive the controls are, how the artwork looks, and how "industrial" the whole feel of the cabinet is.
And besides, while building these cabinets is a lot of work (especially for such a woodworking novice such as myself), it is a lot of fun. And, y'know, it keeps me out of trouble, which is always a good thing.
So onward and upward...