I am going to replace the home PC (3 yrs old; 2.x gighertz + 1 gig of ram + still plenty of hdd space) with a tricked out Vista box within the next few weeks. I plan to get a KVM switch and install Linux or BSD on the old machine. So my dilemma is: which linux or BSD ditro should I install? My requirements & nice-to-haves are listed below:

Requirements:
stable OS
good catalog of available freeware utilities
must be compatible with Firefox and OpenOffice
slick GUI capabilities
ability to remotely log in to the GUI (similar to how I use Remote Desktop to access XP machines)
decent support for USB devices

Nice-to-have:
ability to use as print server
ability to use as file server (and allow other pcs to map to its drives)

Which distro would you recommend and why?