Step 3: Building the cabinet.
screw everything together, fill in all the gaps and holes with spakling compound, then sand it back nice and smooth.
I haven't yet attached legs to my cabinet, because I'm trying to design collapsable legs that will still be able to take the weight of the cabinet. i want to be able to pack it up and put it in the boot of a car in 15 minutes, so I can take it to parties, etc. if you don't need your cabinet to be portable, then build sturdy legs for it - I'd use even lengths of 4x4 bolted and braced on each inside corner.
you can decorate your cabinet any way you choose - getting professionally printed graphics is probably the most aesthetically pleasing method, but it can be expensive. i designed mine based on a NES controller coffee table I built. If you want to paint it a solid colour, you can acheive a smooth finish by first spraying it with primer, and then a coat of satin black or whatever spray you want. sand it back, apply another coat, and sand and paint another 2 or 3 times. this will create a nice, smooth, even finish. once you have everything painted, you can move onto the next step - electronics.