I've created 3 cabinets so far from existing parted out games. My advise is spend the money on the PC, the monitors, a good sound system, flashers, solenoids, shaker in that order. Flashers make a bigger effect than solenoids/shaker, etc. Its not cheap to make, but like a previous poster said it will stay in your gameroom if you build it properly. Make a cheap cab and you'll regret it and it will ruin the effect.

We've gone from an interesting emulator to a simulator in the past year or so. The cabinets you can build now are way more fun and play like a hybrid pinball/video game. Adding physical elements the cabinet increases the simulation. It will never replace a pinball machine, but it's a great addition to a gameroom and way more fun than a video game.