Good luck with it, I've not done much myself - I've added a coin button on the front of the panel got 2x U360's installed and same as you LED buttons (white). I already had a spare gaming pc lying around which I've put inside the cab (needs to be strapped down), it's a bit overkill for most mame (Phenom IIx4 965 quad-core @3.4, 4gb geil ultra, Sapphire 58501gb) games but I'm gonna be running some modern pc games/other systems in it as well, so wasn't worth me selling it/downgrading.
Bargain on the monitor! I've toyed with the idea of CRT but my bartop has one and it just made the thing unbelievably heavy, so I kind of vowed not to go back. I know what you mean with the viewing angles, I'm hoping it wont be an issue but will see how it goes. I could always stump up the extra for an arcade monitor but I don't know what the res would be like on modern games.