Word clouds, to me, are things of great beauty. There's something fascinating about them, and endless hours of fun to be had fiddling with color schemes, angles, typefaces, and - of course - the contents. Here are some of my favourite online apps for creating them:
http://www.wordle.net/ - allows visual formatting, but not much control over content.
http://tagcrowd.com/ - more control over content with this one (minimum frequency, group similar words, etc.) but much less satisfying visually.
http://www.tagxedo.com/ - I've not tried this one (content has to be online) but it looks like fun, forming tag clouds into images.
http://www.alphaworks.ibm.com/tech/wordcloud - This is a command line tool, useful for analysing data stored offline. Requires login to IBM developer site.
