The name "Vista" has been seen by some as not fully thought out. There are a number of companies named Vista and many which have products which are. While none are operating systems, it seems likely that there could be some legal wrangling. A nice article on the topic is to be found on the Washington Post (http://www.washingtonpost.com/wp-dyn/content/article/2005/07/26/AR2005072601673.html).

Wondering what's in Vista? C|Net has a helpful article on it (http://news.com.com/FAQ+Getting+a+handle+on+Windows+Vista/2100-1016_3-5672671.html?tag=nl).