the gateway idea is nice, but ics sucks.
escpecialy when you have to reboot your 'frontline' machine,
my preferance would be to use the adapter and set up an old 100 mhz pc as your nat/firewall/gateway machine, the software is available free,
Freesco And
Smoothwall are two of my fav's.
this will enable you to have all pc's connected at the same time (via your network hub/switch). and the best thing about this sytem is, its realy cheap to add more ports to your network as your not relying on an overpriced 4 port router who's command language will be out dated in six months and wont be supported within 2 years