The Cisco/Linksys WAG54Gv2Linksys Australia Product Page
The V2 WAG54G is a Wireless-G ADSL2/2+ Gateway with a 4 port switch + NAT/Firewall/Router etc
It is significantly enhanced over the v1 and v1.2 WAGs which were total lemons.
The Australian version features 8MB of flash as compared to the European version which only has 4MB, means more and better features in the firmware are possible.
32MB of RAM and a Texas Instruments AR7 @ 150MHz, makes for a fairly powerful cheap router
Linux based, but not as well supported by the OpenWRT community, as the WRT54G, yet. http://wiki.openwrt.org/AR7Port
Has VOIP compatible QoS
built in which works quite well with the Sipura 3000
, at least in the 18.104.22.168 firmware