There is nothing you should be more wary of than a benchmark that matches your pre-existing intuition. It'll lead you to ignore serious methodological issues, without any sound scientific (or any other epistemological) reason.
https://speakerdeck.com/alex/benchmarking is a slide deck I gave at my office on how to do better benchmarking
EDIT: I should probably mention I work at Rackspace, and thus everything I say on this subject should be taken with appropriate grains of sand :)