Have just successfully upgraded wordpress to the latest and greatest 2.5 and I think they have done a really good job. WordPress boasts a very powerful blogging engine and most importantly, it is very user friendly and easy to install.
For those who have K2 on the previous version of wordpress, you might encounter a fatal error after upgading. Simply upgade to K2 RC5 from the SVN nightly release while Steve from K2 is working hard to push out a release.
I am currently using this SVN that appears to be working fine except for some quirks with the layout: