My blog is not that popular with millions of visits of a month but it's decent enough to choke and die under most shared hosting. Well, I once setup my Wordpress Blog to run on Linode's cheapest server with nginx, wp-cache, and all the jazz. But then I kinda remained tense most of the time and even minor instances at the wrong time give me the bumps.

Now, I use Page.ly and CloudFlare in the front (WPEngine is an equally good host and I'm considering for another Wordpress Setup of mine) and I don't even care about the host, I just care about my blog and how to update it with articles. It's costlier but it comes with it's reward.