The promise of the Wordpress developers that the transition to 2.5 is no more difficult than usual, is great. My self-experimentation has shown that they have by and large kept their promise. Because after seeing the usual upgrade steps had passed, were missing on my page 2 sidebars. Since I've only ever looked not bad.
However, one should look at not only his upgrade that plugins are suitable for the new version, but also control the used theme. My i3Theme is fortunately of the WordPress 2.5 Themes supported, but in the new version 1.6. The lists for the support plugins and themes supporting it are directly from wordpress.org.
If you're upgrading to a new theme or a new version of the ancient themes, should be the händischen changes, such as the integration of the script for Google Analytics or the tag cloud in the Sitebar not forgotten.
If one has thought of everything, so a WordPress receives a tidy dashboard. How far I have the new features take advantage of wordpress 2.5, will be shown in practice. But since it's spring now, was a bit of tidying up mandatory 
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