Paul Jones has come back around and revisited the benchmarking setup he's created and has rerun some of the baselines on a new, clean EC2 instance and posted the results to his blog. These benchmarks were run using Apache's ab, Acme's http_load and joedog's siege.
I thought it might be interesting to see what each of them reports for the baseline "index.html" and "index.php" cases on the new Amazon EC2 setup (using a 64-bit OS on an m1.large instance). The results follow (all are at 10 concurrent users, averaged over 5 one-minute runs).
In his results, he shows quite different numbers for the "absolute" requests per second that each of the tools registered. There were some differences from the previous benchmark runs that could have been caused by the update in Ubuntu version and using a 64-bit instance over a 32-bit instance on the EC2 setup.