The problem on the WRT54GS seems to be configuring the router to allow any LAN or WLAN connection to achieve the full 10MB. I am researching this and playing with settings. I know that I get reliable and consistent download and upload speeds that approach the maximum for a 10MB connection whith one pc directly connected to the cable modem.
On initial set up I seemed to have 2MB+ download and 470KB upload from both wired and wifi connected pc's. I now have 4MB+ download and 200KB upload on all pc's. If I take the router out of the equation and wire a pc directly to the modem I get the full 10MB service.
My challenge is to get the full 10MB through the router to all pc's and I'm looking at Quality of Service information and researching as much as I can.
There are loads of threads on the forum at
www.linksysinfo.org relating to this issue. Very few definitive comments and answers though.