Lots of consumer routers can handle this today (Score 2, Informative)

In some countries, like here in Sweden, this was a problem 8-9 years or so ago (when we started getting 100/100mbit at home) and was under much discussion then, but I fail to see how it is a problem now. There are plenty of consumer home routers now that can handle this. I can highly recommend the more expensive DLINK routers, yes I know, the cheaper ones are ... not very good. Have a look at the DIR-655 or all of the DIR8xx series, excellent in my and many others experience. Stable, fast, never needed a reboot and has no performance problems for high-speed downloads, be it direct downloads from a single source or hundreds/thousands of connections in torrents. Have no problems maxing out my 100/100 connection. Even has traffic shaping so your downloads or uploads don't interfere (noticeably) with your gaming or browsing etc.

Pfsenese or m0n0wall might be more fun though, but if you don't run it on some small embedded device (but still have to find one powerful enough) it will draw more power than a small modern above average home router.

See this chart of actual WAN-LAN throughput for home routers: http://www.smallnetbuilder.com/component/option,com_chart/Itemid,189/

Mind you you will have to use wired not wifi for those speeds.