Easy.
Linksys WRT54G, versions 1-4, running DD-WRT or Tomato firmware. They're out there for fairly cheap.
They are also available as the WRT54GL, after Linksys discovered what folks are doing to upgrade them with the aftermarket Linux firmware.
The WRT54GS is also a good one, adding SpeedBoost capability on the wireless half of the router.
They all have 802.11g wireless, adjustable transmission power, and with the DD-WRT or Tomato, serious capability for home/small-office.
Once you install the improved (and free) firmware, you get bandwidth monitoring, SNMP, connection logging, all sorts of stuff.
Stay away from the WRT54G versions 5-7. Linksys gutted them, reducing the internal memory capacity and running VXWorks instead of Linux.
More here:
http://en.wikipedia.org/wiki/Linksys_WRT54G_seriesYou will not be disappointed. Mine does yeoman duty, and the home network hits it pretty hard. It's the bottom component in the blue Linksys/Cisco stack shown here:
The Snap Server is my webhost, running through the router to let me grab stuff no matter where I am in the world. My wife VPNs to work through the router, no problems other than having to set our workgroup IP to the 10.10.10.xxx range to avoid conflict with the 192.168.1.xxx her IT guy at the office insists upon.