I used Wordpress the last couple of years. And I used it a lot. Not just my blog used Wordpress but I also run my portfolio (CHRISSP.com) with it. And other than that I used Wordpress for most of the client websites I created in the past years. It might be good for blogs but it is not bad for standard 'CMS' usage either.
But now while planning the relaunch of this blog I found out about a tool called SecondCrack by Marco Arment. It is not what you expect nowadays cause it creates static HTML files and saves your post in standard text files (Markdown formatted). I just started to use it but I already can see the drastic reduction in CPU and RAM power used by my site. That is due to the fact that serving static HTML files is much less of a hassle than serving PHP files which need to be compiled and MySQL requests which need to be processed before the site can be served to the user.
So far I am happy with SecondCrack.
Let's see if this will prove to be a good choice!