Hitwise created a list of the top 20 Google properties. The most used Google services, other than web search, are Image Search and Gmail. The rest have a pretty low share. It's interesting to see that Froogle is more used than Google Video and that many new services (Google Calendar, Google Finance) don't have a big audience, although they are integrated with Google (Google Calendar is linked in Gmail, Google Finance is the first result for any stock-related search).
In November last year, the first 10 Google services were:
1. Google Web Search: 79.9%
2. Google Image Search: 9.2%
3. Google Mail/Gmail: 5.6%
4. Google News: 1.6%
5. Google Maps: 0.8%
6. Froogle: 0.7%
7. Google Scholar: 0.6%
8. Google Groups/Groups 2 Beta: 0.5%
9. Google Print (Google Books): 0.4%
10. Google Earth: 0.3%
So the Google service with the highest rise is Google Video.
21 minutes ago