We have a nominal 512k BT ADSL link. I use click here to test my speeds from a server in LA. I think that's a pretty stiff test.
This morning (over WiFi) the results were 750k down and 240 up but somedays I can achieve 1600k up.
All these test are carried out over a 802.11b WiFi network that has 1 Desktop cabled to the Gateway and another WiFi'd. In addition we can have upto 3 laptops on at the same time.
We have 2 Access Points on the network and we do see difference in performance between these when using WiFi.
Without actually producing test results we feel the best performer is a Toshiba AP closely followed by a DLink and the WiFi produced by the Actiontec Gateway is easily the slowest. All are 802.11b only.