The key here is expansion. Are you intending to expand your setup to include RECORDING? Band in a box is only editing existing midi/audio files to create new music. Actual recording is an entirely different animal which places other performance requirements on a computer. The audio interface, number of tracks, Plugin and or samples count, monitoring, etc etc etc. It can be simple or complex, and the variables all determine the choice of computer components AND the OS. For instance, a simple BAND IN THE BOX computer could easily run on a P4 2.8 running WinXP. However, a modern Protools rig running lots of samples and plugins requires an i7 x58 or SandyBridge CPU with compatible mobo, and Win7, as WinXP only allows a max of 4gig of ram, where as Win 7 can access up to 24gig of ram(I believe). Anyway, I would suggest asking yourself what your future aspirations are. This can possibly keep you from wasting time and money on something now that will only have to be upgraded in the future.
Oh, and then there is Apple. Which is an entirely different animal than a PC. If you ARE planning on expanding into AUDIO RECORDING, I'd suggest doing LOTS of research on what is best for your intended path. The options are mind boggleing in this day and age. Each platform has it's pro's and con's. However, your intended destination will give you some clues. For instance, PC's can be a DIY project. Lot's of people build their own PC for a DAW. But very few people can build an Apple...if any. And the software is another animal that will determine a platform choice as well. Good luck.
