Need help with LED Cube

I'm new to Microcontrollers and I recently purchased the Arduino Uno and Mega 2560. For my first project I'm making a 5X5X5 LED cube. I'm using 3mm diffused blue LED's. Should I control the LED cube with the Uno or Mega 2560? One tutorial that I read said to use a constant current sink driver. Should I use it and what are the advantages of using it? I also wanted to know where I can find a plastic case to cover the cube. I want it to play music when it displays the animation and want to have buttons so I have multiple animation patterns to choose from and each one plays a different song. This is the tutorial that I'm following: , it uses 5 x 3-8 line decoders (also known as DEMUX) to convert a 5-bit parallel binary output to a one-hot 25-bit parallel output, which drives the columns of LEDs. Is there a better tutorial that I should follow? I want to make my own PCBoard like in the tutorial that I'm following but he designed it so that the circuitry and Arduino are beside of the cube and not underneath like I want it. Does anyone know of a design where it's underneath? Would it be hard to make the LEDs dimmable? This is how I would like my cubed to look like: , I appreciate any help you guys can offer.

Bit of a cop-out but or*4*4_%28Rainbowduino_Compatible%29