As a network engineer at a company with 2x 1 GigE connections to the internet I can vouch for the fact that your first bandwidth limiting factor is going to be your firewalls. Our Cisco PIX 501s are only rated for a few hundered Mb/s and even then cost alot more $$ (or Euros in this case) then a home user would be willing to pay. Switch ASIC based ACLs may be fine for an ordinary home user (though nice Gig switches aren't cheap either), but if you want to use your shiny bandwidth for any sort of business and then you need a real firewall.