I have found Tagadelic works very well out of the box and is, to my hours of research and knowledge, the only plug & play feature for a tag cloud available for Drupal 7.
This is the only problem I've run into--I want the functionality of Tagadelic but do not need it in the "cloud" format. I need my tag cloud to be in a list from most popular to least popular and no size variation. For example:
Item x
Item h
Item j
Item o
Item 4
Obviously the most popular item being 'Item x' and the least popular item being 'Item 4' How can Tagadelic be modified to this as I know it will require more than a CSS fix? Or is there a better option than Tagadelic?