gigabit fiber network cards

Hello, Does anyone have any recommendations on a good gigabit network fiber card for Suse Linux? We are expanding to two buildings and are going to put a gigabit fiber backbone between the two. I have looked at a couple of options (switches, routers, converters......) but I think I would like to put a couple of Linux boxes at the end of each connection to do the routing (and so I can control what goes through and what does not). Any suggestions would be greatly appreciated. Thanks Jon