Where do open source IT solutions make the most sense, and what are your favorites?

Editors at Focus recently published "Open Source, Open World," a time line of open source developments in multiple fields across the globe (at http://www.focus.com/fyi/information-technology/open-source-open-wo...). But where business technology is concerned, where do open source solutions make the most business sense -- in the infrastructure, on users' systems, on servers, elsewhere or not at all? And what specific open source solutions do you like best, and why?

We have a Focus Community member that is looking for some help with this - any insight?

http://www.focus.com/groups/information-technology/topics/view/wher...