Computer Do Over

So, the Dell CPU died today. We have most of our cd's on itunes in Apple Lossless and have most of them saved on an external hard drive. We thought it was broken but turns out it is okay and the computer is fried, so we will start over. We run a Squeezebox with a DAC for this. MY question is considering a complete do over - do we stay with PC or go to a MAC? We are reading up on Mac Mini - and wondering if this is the way to go. What is Snow Leopard and is this needed? Appreciate any thoughts and suggestions.