I mentioned earlier that I had moved my sites over to Slicehost. My reasoning for this was performance. Here is a graph that proves that performance out as seen by the Google robot. This graph shows the response times that Google was seeing when it spidered my site. The crazy noise on the left is Dreamhost. The nice, flat, consistently fast response on the right is Slicehost.
The world of SEO is filled with black magic, but I have had people that know there stuff highlight that site behavior does impact your ranking in Google. This intuitively makes sense. If your site is slow or eratic in response, Google is going to give a bad experience to the visitor they send to you. If you are fast and always available, it will be good. It's easy to see how this could be used to influence search ranking, but it's not provable.
Either way this is a good thing (tm) and it's good confirmation to see the site performance improvement vetted from a third party like Google.