B has better range then G...
I've gotten a block out of B, but only a building with G, wireless networks
drop to B if the G signal isn't high enough, in addition, most wireless
specs, the receive sensitivity is much higher for B then G, lastly, the
power output is higher for B.
But as for N access points, I still go with the router, turn off the DHCP
server, and any NAT features and you have an access point.
Some Belkin (shudders at suggesting this brand though) routers have an
option in the internal web server to turn it into a Access Point...
Ignore the WAN or Internet port on the router, plug your network into one of
the "PC" ports.
The main advantage of doing it this way, and the reason I do, is because
then you also end up with 3 more ports as a switch in the AP location.
Kevin