Mini-ITX sytems are really easy to build and will be really small. If you don't want to build, then just find the smallest system to can find. The more powerfull the CPU, the better for Web and FTP serving. OS: I'd go Win2k or XP and use IIS (for your web server) cause it come they come with it. then I use serve-u ftp server. it's easy and fairly configurable.