I switched to a Netgear WNR3500L with DD-WRT and my internet speed went up exponentially. I just pay for Shaw Regular and get 27-29 Mb/s.
My WRT54G with the recommended stable DD-WRT would only pull 14MB/s.
Upload is a different story. It's capped at 0.95 MB/s no matter what.
A better real world test is to download something from a fast server.
IE. Apple or Nvidia. I can download iTunes at an average speed of 2.5MB/sec and peak at 3 MB/sec.