Google Insights for Search is a great way to see what the World is searching for. You can compare search volumes across geographical regions and time
A few examples:
Top Rising Searches Worldwide
The current Worldwide “hot” list…
Top Rising Searches in the UK
What’s being seached for in the United Kingdom only…
Interest over time in “Kerrison”
How many people have been searching for a given search term (in this case: “Kerrison”)…