Using a broadband router on a connection >1Mbps?
I knew a lot of ADSL modems capped at 24Mbps, but until recently I assumed the home broadband routers (ethernet presentation on LAN and WAN interfaces) would have close to 100Mbps throughput - it was only after a colleague asked me about this that I looked into it.
The best illustration I found is the chart over at Tom's Networking which shows "WAN to LAN throughput" for a number of routers they tested.
(There are other charts available in the drop-down list also.)
As 2, 4, 8, 10, 24 and even 100Mbps Internet connections are becoming more widely available in homes, if you are using a broadband router then you might never achieve the maximum potential of your bandwidth.
Now, as speeds get higher you might find it more and more difficult to saturate your Internet connection from one server, but once you get multiple streams or clients into the equation you could hit a ceiling in the router before anything else.
Factor in the effect of SPI, firewalls, privacy filters or VPN endpoints and you could be reducing the speed further.
Could be something to bear in mind if you're not sure if the performance you are getting from your router is what you would expect, or if you are considering buying one for a high-bandwidth connection now that "Broadband Britain" is starting to catch up with the rest of Europe ;)
